CHEMISTRY SOLUTIONS GRADE VI, VII, VIII & IX ALL CHAPTERS

CHEMISTRY SOLUTIONS

GRADE VI, VII, VIII & IX

ALL CHAPTERS

Propel Academy

CHAPTER 1 MATTER AND ITS

PROPERTIES

Chemistry

© Dr. Ravi’s Educational Research and Development Center 1

Serial No.

Answers Explanations

1 b It has no mass and volume

2 b It has no volume and mass

3 a He found Brownian motion

4 c These two have volume and mass

5 c Other used to measure liquid and length

6 D Matter has mass and volume

Serial No.


1 b Solid, liquid and gas

2 c Liquid water cannot persist at the Moon's surface

3 d Solid, liquid and gas phases changed due to temperature and pressure

4 d Freezing and melting points are same

5 a Temperature is constant

6 a Boiling means it absorbs water

Introductory Exercise 1


Serial No.


1 c Stone is a solid

2 c Plastic is a solid and foam is not a liquid

3 d We can’t change the mass by twisting the balloon

4 b Water has no definite volume and shape

5 c Object C has largest volume

6 c Both are matters

7 b Milk has no definite volume

8 a Ice cube melt and form liquid

9 b Cotton bud is solid and juice is a liquid


Class VI C1:Matter and its properties


7 c Freezing and melting points are same

8 a The strength of bond also loses

9 b Latent means hidden

10 b For 1 kg it needs 3.34

11 a Condensation and boiling point same

12 d Water vapour at 373 has more energy

13 a It can undergo sublimation

14 d We can change all with temperature

15 b We can change only gas

Serial No.


1 d All these are gaseous state

2 a Solid to liquid by melting and liquid to gas by boiling

3 b Gaseous to liquid is condensation

4 d Boiling solid absorbs heat

5 c Non-living things are also matter

6 a Fire is energy

7 b If we pour hot water, the glass will expand

8 c It has no volume and mass

9 a Solids have definite volume, shape and mass

10 a CO2 never support burning

11 a Shadows and reflections are not matter

12 c Sound is not a matter, oil has no definite shape

13 c The shape of containers are different

14 d The ice melt into water

15 d That’s why it absorb water

16 a heating air molecules causes them to get excited

17 d It has no definite volume, it is a liquid

18 d Milk already hot, so it lose its heat

Serial No.


1 C Solids have a definite shape

2 D The particles in a liquid are not close together with regular arrangement

3 B

LEVEL 1 Exercise 1 Single correct objective questions

Exercise 2 Statement Type



Serial No.


1 c Oxygen is in gaseous state

2 d It has definite shape

3 b It assumes the shape of the container

4 a It is the fourth state of matter

1 c Iodine is a sublimate

2 d Water changes into water vapour by evaporation

3 a Condensation means water change to ice

4 b Boiling point ice to water and water to steam

Serial No.


1 a Evaporation can takes place at any temperature

2 b After rain humidity will increase

3 d The solid form undergo sublimation is called sublime

4 a Ammonium chloride undergo sublimation process

5 c Intermolecular spaces are large in gases

Serial No.


1 c, d Heat and light are not matter

2 a, c, d Matter cannot be seen

3 a, b, c We can’t make or destroy mass

4 a,c Air lost from one balloon

5 b, c Air can be compressed

6 a, c It contain more water vapour

7 a, d It never decrease its volume

8 c, d Boiling absorb heat

9 a Substance z is not water

10 a, c Cooling make water droplets

11 b, d Solid has a definite shape

12 d This is a liquid so takes the shape of a container

13 b Definite shape only ball have

14 a, b, c, d Book is a matter

Exercise 3 Match the following

LEVEL 2 Exercise 4 Assertion and reason

Exercise 5 One or more than one correct options



15 a, c All are matter and has same mass

Serial No.


1 d Water cannot be compressed

2 b It is in balanced state

3 d Air can be compressed

4 d So melting is very slowly

5 b Water occupy some space

6 a These are different states of matter

7 b Three objects have three different shapes

8 a Between 15 and 110 x is liquid,

9 a Because ice is a solid

10 b Matter is more in cotton

11 b,c They are closely packed

12 b 200 water is there

13 a Matter occupy space

14 a It is in balanced state as they have the same volume

15 d Air can be compressed

LEVEL 3 Exercise 6 Questions from/for Olympiads, NTSE

Propel Academy

CHAPTER 2 BASICS

OFCHEMISTRY

Chemistry


Serial No.


1 d Symbol of Aluminium Al

2 a Symbol of Boron is B

3 c Aurum is the name of gold

4 d Sodium symbol Na

5 C Iron for Ferrrum

6 c Cupperum is the Latin name of Copper

7 c Cl is the name of chlorine

Serial No.


1 a They have no charge

2 a Neutron have no charge

3 b Atomic number z

4 d The number of protons in the nucleus of an atom

5 a Mass number – atomic number

6 b Mass number A

7 d The atomic number of sodium is 11


Serial No.


1 d Both protons and neutrons

2 a, b It contain a single proton and single electron

3 d It contains 3 protons, 4 neutrons and 3 electrons

4 d Hydrogen is lighter

5 b Electrons are 1800 times smaller

6 a Both have opposite charge

7 c Neutrons have no force

8 b This is the value of radius



Class VI C2:Basics of Chemistry


8 b One unit negative charge

9 b Electrons are 1837 times smaller

10 b An atom is the smallest particle of an element that has the propertiesof that

11 b A molecule has all the properties like a compound

12 d We can’ t say the nature

13 d Water is a compound

Serial No.


1 b Water contains three atoms

2 d Gold is an alloy

3 b Mass number denoted by A

Serial No.


1 b Copper is Cu

2 d Lead is Pb

3 a Mercury is Hg

4 c Gold is Aurum

1 c Helium is an element

2 d CO2 is a compound

3 b Air is a mixture of all gas

4 a He+ is an ion

Serial No.


1 b Protons present inside and electron outside

2 d Protons are positively charged particle

3 a Force increased by increasing the charge

4 a Atomic number is the number of protons





Class VI C2:Basics of Chemistry


Serial No.


1 d Proton is a particle

2 b, c It is present inside the nucleus

3 a, b, d Only one proton in hydrogen

4 b, d Salt water is a mixture of salt and water

5 a, b Na for sodium and K for Potassium

6 c 20 represents atomic number, 40 means mass number


Serial No.


1 d Au for gold, Hg mercury

2 c Li for Lithium

3 b Au for Gold

4 a Pb for lead

5 a Ag for silver

6 a Calcium atomic weight is 40

7 a Magnesium contain 12, 13 or 14 neutrons

8 d Helium has 4 number of protons

9 b Atomic number means number of protons

10 d atomic weight – atomic number= number of neutrons

11 d Equal number of protons and electrons

12 a Protons, electrons and neutrons

13 a John Dalton assumed atoms to be tiny particles

14 a Inside the nucleus only protons and neutrons present

15 d Atomic weight means number of protons + neutrons

16 c Neon has 10 number of electrons

17 a Inside orbit called core

18 b Outside orbit contain 8 electrons

Propel Academy

CHAPTER 3 WATER AND ITS PROPTERTIES

Chemistry


Serial No

Answers Explanation

1 b Water contains hydrogen and oxygen

2 b Water contains hydrogen and oxygen

3 b Steam is essentially water in a gas-like state.

4 c Water changes into steam by 1000c

5 a It is condensation

6 d All are natural sources

7 c Our body weight contains 70% water

Serial No

Answers Explanation

1 d B & D processes are condensation

2 b C is the step which has no change in the state

3 d Water can change from one state to another

4 c Through condensation gas can change to liquid and liquid can change to solid

5 d Hailstones are snow.

6 d Because it has a definite shape

7 b After 1 hr its shape changed

8 d In ice water it ice cube melt slowly

9 a 00c water in solid state

10 b, c X did not change its shape in both pictures.

Serial No

Answers Explanation

1 b Ice is frozen water

2 d Oxygen is anion and hydrogen is cation

3 b Both the statements are correct

4 Wrong Question




Calss VI C3:Water and its properties


Serial No

Answers Explanation

1 a, b Salt can reduce melting point

2 b, c It can increase the amount of water vapour

3 c, d Sweating of animal is not related with water cycle

4 b, d Plants reduce pollution

5 b, c, d Remove trees cause soil erosion

6 a, c They is no relation with taste and colour

7 b, d If heat is not there, water can’t change its state

8 a,b, c, d Humidity more means evaporation less

9 a, b,d Don’t waste water

Serial No

Answers Explanation

1 d Only hard water form sticky scum

2 a Increase level CO2 cause global warming

3 b Eutrophication leads to the death of fish

4 b Ice has a regular crystalline structure

5 d Two atom hydrogen and one atom of oxygen

Serial No

Answers Explanation

1 c The amount of water vapour more in air

2 b We have to take same amount of water

3 d The amount of water will increase

4 d Same level of water

5 b Cube changed to water then gas

6 d So it can easily dry

Composition of Air

Serial No.

Answers Explanation

1 b Air occupies empty spaces

2 c Breathing and combustion need oxygen

3 d All others are noble gases







4 c Living things need oxygen

5 a Villages are good for health

6 d Air can expand, it has mass

Serial No.

Answers Explanation

1 c Sail boats are not flying in air

2 b Plants can absorb only nitrates

3 c Main part of protein is nitrogen

4 b The size of that bag is small

5 c Water vapour present in the air forms mist

6 c Water and ice cannot be compressed

7 a Option a. air occupies space option b. air has definite volume

8 c The amount of CO2 is higher

9 a CO2 is more than oxygen

10 c Air occupy full volume

Serial No.

Answers Explanation

1 c Air is necessary for burning of objects

2 c Nitrogen in air not essential for growth of plants

3 b Both the statements are correct

Serial No.

Answers Explanation

1 c The amount of nitrogen is highest

2 d Oxygen in the air is 21%

3 b CO2 amount is very less in air

4 a All noble gases together form 0.94%

1 d Oxygen helps in combustion

2 a It is a greenhouse gas

3 c It is the process of nitrification

4 b Presence of chlorophyll






Serial No.

Answers Explanation

1 a The one which occupy space and has mass is called matter

2 a That’s why they are called greenhouse gases

3 d It is not a decay process

4 c CO2 is a greenhouse gas

5 b They also cause water pollution

6 a Air consists of different gases

Serial No.

Answers Explanation

1 a, b, d The inhaled air is also not so clean

2 a, b, c We cannot see air

3 d Air has mass we can conclude it

4 a, d Air can be compresses

5 a, b Air has mass and occupy space

6 a, c, d Light is not an important factor

7 a, b, c CO2 used in fizzy drinks

Serial No.

Answers Explanation

1 c We cannot increase the level of water

2 b We cannot changed the volume

3 a 40 water is there

4 c When water cooled, it never changes to oxygen

5 d We can carry more air

6 C Total amount of water 1000, container volume 3000 that means air is 2000, take 500 water, increase the amount of air

7 c Plants need CO2 to make food




Propel Academy

CHAPTER 4 ELEMENTS,

COMPOUNDS AND MIXTURES

Chemistry


Serial No.


1 c Sulphur is a polyatomic element

2 a All others are diatomic elements

3 d They are less reactive

4 c Graphite is an allotrope of carbon

5 c Total 114 elements identified

6 c Mercury is a liquid metal

Serial No.


1 a Soil is a solid

2 c it is the weight of hydrogen and oxygen

3 b Bi means two

4 a Neutral charge

5 a Covalent compound

Serial No.


1 d Nitrogen and oxygen are 2 main gases

2 a Water with CO2

3 b We are using turpentine

4 a Example all solutions

5 d Copper and tin

6 a Water is a compound

Serial No.


1 c It is a charged particle





Class VI C4:Elements, Compounds & Mixtures


2 a CO2 is a gas with different property

3 d Total 114 elements

4 a Mercury is the liquid metal

5 b Tin-Sn, mercury- Hg

6 a Only atoms exits independently

7 b It has the same property-example solution

8 d All solutions are homogenous

9 a,d He is a monoatomic

10 a Sodium is diatomic

Serial No.


1 c metals are good conductors

2 b Metalloids show the property of both metals and non-metals

3 d Statement 1 is false

4 Question not correct

Serial No.


1 d Boron is a semi-metal

2 c Helium is a noble gas

3 b Graphite is a non-metal

4 a Sodium is a metal

1 c Silver contain one atom

2 d Oxygen is a diatomic

3 a Sulphur is a polyatomic

4 b Ozone contain three atoms

Serial No.


1 a, b, c, d All statements are true

2 a, b, c, d Metals have high boiling and melting point

3 a, b, c, d All are metals

4 a, b, c, d All elements atomicity are same

5 a Only oxygen have same type of atom

6 c This method used to split oxygen and hydrogen






7 a, c AlCl is not a compound

8 b It is the molecule of the compound

9 b It contain two kinds of atoms

10 a, b, d Graphite is a non-metal

11 a 7 elements occur as metalloids

12 a, b, c,d These are the three classifications

13 d Others are having more than one type of atom

14 c Oxygen, nitrogen are examples

15 d Air contain many gases

16 a,b, c,d They have one definite ratio

17 a Water and CO2mixed to form soda water

18 a It contains acetic acid

Serial No.


1 b We can make any shape from metals

2 c Mercury and Gallium are liquid metals at 30oc

3 b Both statements are true

4 a

5 b Compound of metal with sulphur is metal sulphides

6 c Pure water is not a mixture

7 b

8 c 8 metalloids exist in periodic table

Serial No.


1 d They are poor conductors of electricity

2 a Form of carbon

3 d These all gases are colourless

4 d These gases are non-metals

5 d Noble gases

6 c oxygen is most abundant= 46.6%

7 d Coal is not a compound

8 b Both are solids

9 b This is heterogeneous mixture

10 a Lime water is calcium carbonate

11 c It is a mixture of gold and mercury

12 d All are pure

13 d All these are the characters of elements





14 a Mixture of two substance

15 d Particle are atom or molecules

16 c Iron is a metal

17 c Oxygen is a non-metal

18 b It is the chemical combination

19 b Carbon found in these

20 a Elements we can’t separate

21 d All these are alloys

22 b Water is a compound

23 b CO2 is a compound

24 c Two or more atoms are present

25 a This is element

26 a Potassium and sodium are highly reactive

27 c These are precious metals

Propel Academy

CHAPTER 5 SORTING AND SEPARATION

Chemistry


Serial No.


1 b Centrifugation apply for colloidal particles

2 d All we can used to separate

3 a Centrifugation apply for colloidal particles

4 c Boiling point is less

5 d Water is volatile liquid

Serial No.


1 d Chromatography used to separate colours

2 b Water is the heavier than benzene

3 a Chloroform is heavier than water

4 d Chromatography used to separate colours

5 a Filter paper is used in chromatography

Serial No.


1 c one of the components of the mixture sublimes on heating

2 b light weight constituents is blown away by air

3 c These are big one, we can pick it easily

4 c Beads we can pick with hands

5 b Decantation not disturbing the sediments

6 c filtration is used to separate undissolved particles

7 b Ammonium chloride is a sublimate

8 b Common salt and water separated by this technique

9 a Chalk and water is an example

10 d Distillation make pure water

11 c Acetone dissolves nail polish

12 c We are using porous material for filtration

13 c Sedimented material is called residue




Class VI C5: Separation of Substances


14 b Chloroform easily evaporated

15 c Non-volatile solid

16 d Water will evaporate

Serial No.


1 d Chromatography is used to separate amino acids

2 d Evaporation is not suitable for all the solid liquid mixtures

3 b Dry ice is sublimable solid

1 d Separating chalk and water with filtration method

2 c Ethyl alcohol evaporate easily

3 a Iodine is the sublime

4 b We can separate cream from milk by centrifugation

1 a Paint dissolved in turpentine

2 c Iodine is dissolved in benzene

3 b Oil easily dissolved in gasoline

4 d Acetone dissolves nail polish

1 d grain was separated by hand

2 d Both are solids so we can’t separate by sedimentation

3 b Sand and salt can be separated by this method

4 a The method of separation of mixtures where one of the components is magnetic in nature

5 a So we can easily separate them

6 b Chalk and water separate by filtration

7 c Chromatography used to separate colours

1 d Remove waste material and obtain pure materials

2 a, d We can separate blood constituents

3 a, b,c, d Cobalt is a magnetic substance





Class VI C5: Separation of Substances


4 a, b, c, d

All these depends upon separation

5 a Sublime means solid to gas

6 a Simple distillation

7 b Filter paper is used in filtration

8 c We can make chromatograph

9 a, c Sand and saw dust separated by using gravity

10 b Iodine is a sublime

11 a Sand is heavier

12 b If paper using. That is paper chromatography

13 b Water is a universalsolvent

14 C It is a water condensor

15 d Iron is a magnetic substance

1 c Sugar water pass through filter paper

2 b First separate sand water by filtration

3 c Separating funnel

4 d These are inert gases

5 a It is a liquid metal

6 a, d Salt mixed with sand separated by filtration

7 b Both these processes we can see

8 d Camphor is a sublime

9 b Through this method we can separate alcohol and water

10 b Chromatography used to separate colours

11 a Properties are totally different

12 a It is called decantation

13 d Mixture contains all

14 c These are separated by distillation

15 c Ammonium chloride is a sublime

16 a Fractional distillation separate components of petroleum

17 b Higher evaporate slowly

18 c Solid-liquid heterogeneous mixture

19 a Used to separate cream from milk

20 a, d Water only pass through filter paper


Propel Academy

CHAPTER 1 INTRODUCTION TO CHEMISTRY

Chemistry


Serial No.


1 d Electrons are orbiting outside the nucleus

2 b Hydrogen contain least number of protons

3 d Lithium contains all three particles

4 d Hydrogen is lighter because it contains 1 protons

5 b Electron has negligible mass

6 a Because they have opposite charges

7 c Because neutron has no charge

Serial No.


1 d Al is the correct symbol

2 a B is Boron

3 c Ag is silver

4 d S is for sulphur

5 c Ferrum is a Greek word used for iron

6 c Cupperum is the word used for copper

7 b Cl is used for Chlorine

8 a Ag is for silver

9 a It is coming from a word Plumbum

10 c Hydrargyrum is the name for mercury

1 2 The number of electrons in an orbit is equal to 2n2



4 Orbit Electrons are moving through orbit

5 Two Magnesium has 2 valence electrons

6 Three Boron has 3 valence electrons

7 Two Boron has 5 electrons. 2 will be present on the inner shell to complete duplet




Class VII C1:Introduction to Chemistry


8 Two Beryllium has 2 core electrons

9 Zero Every atom except hydrogen has core-level electrons

10 One Li and K have one valence electron each.

1 True Oxygen has 2 atoms

2 True The formula is O3

3 True Oxygen has eight electrons, two in the first shell and six in the outer shell, giving it a valency of two

4 True Sodium has 1 valence election

5 True sulfur atoms form cyclic octatomic molecules with chemical formula S8

6 False If an atom gains electrons, it has a net negative charge and is known as an anion

7 False If an atom gains electrons, it has a net negative charge and is known as an anion

8 True Anionic radius is larger than that of parent atom

9 True O2 is actually smaller in size

Serial No.


1 a Atomic mass is high in magnesium

2 d Helium contain very less number of neutrons

3 b Radius of nucleus is smaller

4 d Compounds can be separated by chemical means

5 c Compounds can be separated by chemical means

6 c It becomes the size of a cricket ball

7 a 1015 time taken by hydrogen atom

8 b Sodium fluoride is a compound we can separate by chemical means

9 c Compound contains 2 or more number of atoms

10 d carbon is a non-metal because in elemental form it doesn't form a metallic bond and conduct electricity

Serial No.


1 b Same charges repel

2 d Mixtures are not physical combination of two or more elements






3 d Elements need not be pure substances

4 c 114 elements known in the periodic table

Serial No.


1 a Electronic configuration of Na is 2, 8, 1

2 c Electronic configuration of Mg is 2, 8, 2

3 d Electronic configuration of Li 2, 1

4 b Electronic configuration of Cl 2, 8, 7

1 b Mass number of Helium 4

2 c Mass number of Boron 11

3 a Mass number of Nitrogen 14

4 d Mass number of Oxygen 16

Serial No.


1 d Mendeleev Organized His Table According to Chemical Behavior By 1869

2 b Iodine symbol is I

3 d Mass of an atom depends on mass of protons and mass of neutrons

4 c Mass of a Proton is 1.675 × 10-27 kg.

5 a Positive and negative combine to give zero

Serial No.


1 a Atom is the smallest particle

2 a, b P for Phosphorus and K for Potassium

3 c, d Lead symbol Pb

4 a, c These are in continuous motion and vibrating

5 a These are also continuely moving

6 a, c These two contain only one type of atom

7 b Molecule has all properties

8 a, b, c Water is a compound and air is a mixture

9 c Elemental phosphorous is often written as P4


LEVEL 2 Exercise 4 Assertion and Reason

Exercise 5 One or more than one correct option



10 a All others are monoatomic or diatomic

Serial No.


1 b Aluminium foil contains only aluminium

2 b This contain different compounds

3 b We can’t separate compounds by physical means

4 a Li is heavier ion

5 c O3 is the chemical symbol of ozone

6 b Hydrogen is diatomic

7 d 9, 10, 10 numbers are present

8 d Nucleus contain protons and neutrons

9 d It will not emit any energy

10 c 18+20=38 and add 2

11 d HCl has more atomic weight

12 b Air is a mixture, and salt water is a compound


Propel Academy

CHAPTER 2 PHYSICAL AND

CHEMICAL CHANGES

Chemistry


Serial No.


1 d Swing movement is a periodic change

2 d All these changes we can reverse

3 a We can’t make egg from omelet

4 a It can directly change to gas state

5 c Freezing point

6 a Camphor change from solid to gas

7 a Heat will be released when solid becomes liquid

8 b Camphor is a sublimate

9 d

10 c Heat will be released

11 a Physical changes are reversed

12 a,b,c

13 a Mass will not change

Serial No.


1 b Exothermic means they produce heat

2 a It mixes with oxygen to form magnesium oxide

3 d They prepare entirely different substance

4 d Mercury and oxygen formed

5 b Because it produce heat

6 d CO2 and steam produced in candle wax burning

7 c Heat absorbed or generated




Serial No.


1 d We change the iron into old form

2 b We can’t make the milk again from curd

3 a From water vapour we can make water again

4 b This one also reversible change

Class VII C2: Changes around us


Serial No.


1 c Milk changing to curd is not reversible

2 c Water changing to ice is not a fast change



Serial No.


1 c Bursting of balloon is a fast change

2 d We can change the reaction

3 b That change we can’t reversed

4 a Plants growing is very slow change

1 d Ice changes into water

2 a Salt formed from salt solution

3 b Solid changes to liquid on heating

4 c Water change to water vapour

Serial No.



2 d Splitting of water is a chemical change

3 c Water changes into steam is a physical change

5 d Ice and rubber band both are reversible

6 b Wax can be again make into candle

7 b We can’t make the milk again from curd

8 c There is not an exact period for this change

9 d All the statements are true

10 a It is a chemical change

11 b Colour only changes

12 c Energy released or absorbed

13 b We convert the changes

14 c It is a chemical change

15 c We can’t make them again

16 d We will get the same amount of wax






4 b Both are correct, and the change is permanent

5 b The product and reactants are same amount

6 a It’s a chemical change we can’t reverse

7 a It’s a chemical change we can’t reverse

8 d It is a very slow change

9 a Because we need fruits to eat

10 a Swing moves a certain interval of time

Serial No.


1 b, d Respiration is chemical change

2 a, b , c,d All these changes we can change

3 a, d All these statements are true

4 a, b, c All these are physical changes

5 a, b, d These two changes are chemical changes

6 a, c, d Clock pendulum also a periodic change

7 a, b, c, d All these changes are non-periodic

8 a, c Melting of wax only reversible

9 a, b, c, d All these are fast changes

10 c, d Burning of paper is an irreversible change

11 b, c, d These can be reversed

Serial No.


1 a It is a physical change, no new substances formed

2 b That one also a chemical change

3 No answer

Souring of milk is a not a reversible change

4 d Both are chemical change

5 c Both physical and chemical changes occurs

6 c Example. Burning of candle

7 d Sugar burning is a permanent change

8 b We can see the change

9 A,b,c That one only we can change

10 d Digestion is a chemical change

11 d All these are physical changes

12 a Photosynthesis is a chemical change

13 b Mixing means physical changes only

14 b If we convert milk into curd, it’s an irreversible change





15 c It is a slow change

16 d Occur within a minute means very fast change

17 c It is a physical change

18 d All these can be reversed

19 a, d Germination is a slow change

20 a Physical change only

Propel Academy

CHAPTER 3

AIR AND WATER

Chemistry


Serial No.


1 a Air contain 78% of nitrogen

2 d Krypton and xenon are 2 more inert gas is there

3 a CO2 changes he colour of the lime water

4 c Coal is a solid fuel

5 d Because air is a matter

6 d Air contain different gases

Serial No.


1 c Filling tyres

2 d Moving air is called wind

3 c Molecular weight 18

4 a Ice melted to form water

5 d Camphor is an example

6 b Steam changes to water

Serial No.


1 b Melted ice has smaller volume

2 d They make sticky scum

3 d Sulphates and chlorides

4 d carbonates cause hardness

5 a Two main gases are nitrogen and oxygen

6 d Ratio of oxygen and nitrogen is 1:4

7 a Humidity more there

8 c Solid to liquid by melting

9 d Water vapour condenses to form clouds

10 c Y contain more water and temperature

11 c Water evaporated to form water vapour

12 b They assume the shape of the vessel

13 c These 2 process used to remove hardness




Class VII C3: Air & Water


14 d When a drop of water is poured over anhydrous copper sulphate (white), it turns to blue colour, due to formation of hydrated copper sulphate

15 b Decrease the heat from 80

16 b Hydrogen and oxygen are the 2 components of water

17 b Air contain a lot of gases

18 a Oxygen is involved

19 c Hydrogen is very less in air

20 a The main gases are nitrogen and oxygen

21 b The clouds condense and form rain

22 a Steam condenses to form water

Serial No.


1 b Chlorides cause permanent hardness


3 b Pure water has pH 7

Serial No.


1 d The amount of nitrogen is 78%

2 a Oxygen present in the air is 20 %

3 b CO2 amount is .38%

4 c The amount of argon is .93%

1 c Permutit is also known as zeolite

2 d Anhydrous copper sulphate is used for water test

3 a Temporary hardness by calcium hydrogen carbonate

4 b Permanent hardness caused by CaCl2

Serial No.


1 d Permanent hardness caused by CaCl2




Class VII C3: Air & Water


2 b Water is hydrogen and oxygen

3 a Water is a compound

4 b Air is a colorless gaseous substance

5 a Mountaineers need oxygen at heights

6 d Due to pollution, temp is high in cities

7 b Air is polluted due to firewood gases

Serial No.


1 b, c Melting means solid to liquid

2 a, b, d Air is a matter and mixture

3 a, c Parachute fly using air

4 d Sodium permutit is zeolite

5 a, b, c, d It is not good for washing

6 a, c

7 b, c If we tilt the cup, water enter

8 b Water has no definite shape

9 a, c, d The frog is not getting enough food and air

10 d Air can be compressed easily

Serial No.


1 c Solid to liquid

2 b Temperature affects the state of water

3 b It is actually a matter

4 c Fizzy drinks we are using CO2

5 d Exhaled air contain water vapour

6 c Water vapor coming from air

7 d Compressed air means it increase the volume

8 a Water reaching to rivers in the same form

9 c The air can be compressed

10 a Ice water is there, so air become cooler



Propel Academy

CHAPTER 4

CHEMICAL BONDING

Chemistry

Introductory exercise no 1

Serial No.


1 a Electrons are in the orbits in an atom

2 b Noble gases are mono-atomic in nature

3 d All these are noble gases

4 c Neutral charge

5 c It has 2 electrons


Serial No.


1 a Covalent means sharing

2 d They are more stable

3 b Covalent means sharing electrons

4 a They give electron and become negative

5 b 2 like atoms called non-polar bond

6 b Ionic compounds are soluble


Serial No.


1 a Intramolecule means inside the molecule

2 d Both O and F are electronegative

3 c They have low melting and boiling point

4 a In sulphur we can see the first type

5 a These are bad conductors

6 b Intra within one

Single answer questions

Serial No.


1 b Chemical bond means the attraction and repulsion at particular distance

2 a Helium has two electrons in the outer shell

3 c Having eight electrons total ensures that the atom is stable

4 d All these help the atom to attain stability

5 c Both parent and its ion

6 b 2, 8 is the electronic configuration

7 b Fused one only conduct electricity

8 a They lose electrons and oxidized

9 b They held together by electrostatic force

10 c 3 electrons transfer from AlN

11 c 35 is the atomic number of that atom because it has valency 1

12 a High electro negativity

13 b Aluminium oxide is amphoteric

14 d Water decreases the inter ionic attraction

15 c Both ions are present

16 c It is possible between two similar and dissimilar atoms

17 b Sharing of electrons

18 d There is no free ions and no free electrons in covalent compounds

19 a Covalent means sharing of electrons

20 b Be has the tendency to form covalent bond

21 b Covalent bond formed

22 c 50 electrons are present

23 b The atomic number is 16

Statement Type

Match the following

Serial No.


1 c Covalent bond is formed between two similar atoms

2 d Nucleus contains only protons and neutrons


4 d Covalent bonds are weaker than ionic, so they have low melting point

Serial No.


1 a Sulphur is a covalent compound

2 d Chlorine has single bond

3 b Nitrogen has triple bond

4 c Oxygen has double bond

One or more than one answer

Assertion and reasoning

Serial No.


1 d Covalent bond present in this molecule

2 a It is a stable atom

3 c Covalent is the sharing of electron

4 b Calcium chloride is ionic compound

5 c They may exist solid, liquid or gas

Questions from Olympiad

Serial No.


1 b Pure covalent bonding is only found in elements

2 b Argon is the nearest noble gas

3 c They form covalent bond

4 b It is the other name of ionic bond

5 b Transfer of electrons

6 d All these form covalent bond

7 d Covalent solid having metallic lustre

1 c Sodium valency 1

2 d Aluminium had valency 3

3 a Carbon has a valency of 4

4 b Sulphur has valency 2

Serial No.


1 a, b, c, d They can lose or gain maximum 4 number

2 a They are hard solids

3 b, c, d Hydrogen form hydrogen bond

4 b, c, d These three exhibit octet rule

5 d They don’t undergo chemical reaction quickly

6 a, b, c Ionic compounds are bad conductors

7 b Graphite is a good conductor of electricity

8 d All these form single bonds

9 a, b, c, d All these are the properties

8 b Electrostatic force can be seen

9 b Covalent compounds are soluble in non polar solvents

10 b Octet rule explained this theory

11 a Valence electrons participate in bond formation

12 b 5 is the number of electrons in that atom

13 d Repulsion and attraction equal

14 b Be least electronegative

15 a Energy decreases

16 c The higher the bond energy, the shorter the bond length

17 a The force of attraction that holds the atoms is chemical bond

18 c H-F has strong bond

19 b H and CL, F or Br form polar bond

20 a All others form hydrogen bond

21 b NO3 having covalent bond

22 c Polar covalent bond present in water

Propel Academy

CHAPTER 5 ACIDS, BASES

AND SALTS Chemistry


Serial No.


1 b Tartaric acid present in tamarind

2 a Bases have bitter taste

3 c Curd taste is sour because of lactic acid

4 a Latin, acidus means sour

5 c Salt and water produced

6 b Ants contain formic acid

7 a Grapes also contain tartaric acid

Serial No.


1 a Its acidic in character

2 b Acidic oxides are formed when non-metals react with oxygen

3 a Acid changes the colour from blue to red

4 c That contains at least one oxygen atom and one other element

5 d Bases and acids only form salts

6 c All neutral oxides are gases

7 a Calcium oxide is a basic oxide

8 d They can react with acids and bases

9 a CO2 is an acidic oxide

10 a They are solid in nature

Serial No.


1 d Boric acid used all these

2 a It is the mixture of concentrated HCl and nitric acid

3 d They are used as industrial agent

4 d It is used in explosives

5 b Salt and hydrogen gas




Class VII C5: Acids, Bases & Salts


Serial No.


1 d a crystalline salt having the composition of a mixture of two simple salts

2 c These two are Efflorescent Salts

3 d All these are deliquescent substances

4 a Calcium oxide and H2SO4 are hygroscopic

5 d Formula is C2H2O4

6 b Tomatoes contain oxalic acid

7 c H for hydrogen and Cl for chlorine

8 a Phosphoric used in anti-corrosive paints

9 a Litmus made from lichens

10 b If we mix yellow and whit clour base, it will get red colour

11 a HCl is present in our stomach that is help in digestion

12 d Lemon and orange contain citric acid

13 c Above 7 means it is basic in nature

Serial No.


1 b Litmus paper is commonly used as indicator

2 c pH scale works for acidic and basic solutions


4 c Basic solutions contain OH- ions

5 c pH of blood is slightly basic in nature




Serial No.


1 d Lactic acid present in curd

2 c Vinegar contains acetic acid

3 b Citric acid present in lemon

4 a Oxalic acid present in tomato

1 d Sulfuric acid was called "oil of vitriol”

2 c It was historically called muriatic acid as it produced from rock salt

3 b Magnesium hydroxide is known as milk of magnesia

4 a Calcium hydroxide is quick lime



Serial No.


1 c, d KOH is a strong base and HCl is a strong acid

2 b Less than 7 are acidic

3 b That is why it become more acidic

4 a That is efflorescence

5 c Antacid used for indigestion

6 a Acid gives H+ ions in water

7 b Acids cause tooth decay

8 d That means it is basic

9 b More pH value means more acidic

10 b Base gives OH- in water

11 a, b NaCl is a salt

12 b, d These are acid and salt respectively

13 b Soap contain NaOH

14 a Less than 7 means acidic

15 a Very strong acid and base

16 a Acid gives red colour

17 a,c Tap water pH ranges from 6.5 to 8.5

Serial No.


1 b It is a weak acid


Serial No.


1 d Carbonic acid is an acid

2 b These are the property of bases

3 b Litmus shows different colours

4 c Calcium hypochlorite used for making bleaching powder

5 d All neutral oxides are gases

6 b All acidic oxides are gases

7 d Phosphoric acid used for rust removal

8 b Above 7 means it is basic in nature

9 a So they are hydrated salts





2 b Tooth paste are basic in nature

3 a Means acidic in nature

4 c We can dilute acid by adding water

5 b More ions present

6 a Means acidic

7 b Presence of CO2 in the air

8 d Borax is a base

9 d NaOH is soluble in water

10 b Base change red to blue

11 b Indigestion due to acidity

12 a Ants contain formic acid

13 a Most waste are acids

14 c Normally ants contain this acid

15 d KOH is a base

16 b They gave electrons

17 a Litmus paper is most commonly used

18 a Hydrogen present in all acids

Propel Academy

CHAPTER 1 METALS AND NON-METALS

Chemistry


Serial No.


1 d Elements any be metals, non-metals and metalloids

2 c Elements classified on chemical and physical properties

3 b These two are liquid metals

4 c Luster property shows their shininess

5 a Malleable property make them into thin sheets

6 b Silver has ductile property

7 c They can conduct electricity

8 d Iridium has highest density

9 c Iron has highest boiling point

1 b If it lose electron, it become positive

2 d All have high electropositive character

3 b Valence electrons present in the outermost orbit

4 c Then they become electro negative

5 d Zinc has less electro negativity

6 b Basic oxides are basic in nature

7 c Aluminium is a strong reducing agent

8 d They can appear in any of these state

9 a Gold and silver have luster property

10 b Diamond is the hardest substance

11 d Diamond is the hardest substance

12 b Non-metals are bad conductors

13 a Non-metals have less density

1 a Metals can be drawn into wires

2 a Metallic bonds are seen in metals

3 a Metals like Aluminium acts as reducing agent

4 c Borax made from Boron

5 b It is made from Zinc not from iron

6 d Copper is not used for fireworks

Introductory exercise 1



Class VIII C1: Metals & Non-metals


7 a They react with alkali

8 c Beaching powder made from chlorine

9 a They produced from magnesium

10 b Sulphur used in vulcanization

1 c They show the characters of metals and non-metals

2 a They are looking like metals

3 c Phosphorous is not a metalloid

4 b Metalloids are ductile

5 c Their characters between metals and non-metals

6 b Metalloids are semi-conductors

7 c It used to increase

8 b Tellurium used to give colour for vases

1 b Non-metals are chemically inactive

2 d Silicon is not a noble metal

3 b Silver has some antibacterial properties

4 c These are resistant to corrosion and oxidation

5 b 24 carrot means pure gold

6 c 58.5% gold present

7 d Copper and silver mixed with gold

8 a 750 parts of gold per 1000

1 c Graphite is good conductor

2 c Metals form acidic oxides

3 a, b , d These all are the properties of metal

4 d They are forming acidic oxides

5 a Aluminium has this property

6 c Sodium is a metal

7 d Nitrogen is a non-metal

8 b Graphite has not such kind of property

9 a Iron is a good conductor

10 c Silver has that property

11 b Metals can make sound also

12 a Alnico is the alloy of Aluminium and Nickel






13 b That is Copper sulphate

14 b It is the homogenous mixture

15 b Alloy is homogenous mixture of two or more elements in a definite proportion

16 c Antimony is a metalloid

1 c Symbol of Rubidium Rb

2 a Symbol of Palladium Pd

3 d Symbol of Molybdenum Mo

4 b Symbol of Radium Ra

1 c It is a carbonate ore of Mg

2 d It is an oxide ore of Aluminium

3 b It is a halide ore of Na

4 a Gypsum is a sulphate ore of Ca

1 c Non-metals are generally brittle

2 b It is a good conductor also

3 a That’s why we are writing like this

4 b Sodium can be cut with a knife

5 d The non metal used to make dry cells is graphite

6 b Gangue contains impurities

7 b Mineral + Gangue = ore

Exercise 2 Matrix Type



1 c, d Sodium is very soft

2 a, b Neutralization reaction

3 c It is not releasing hydrogen

4 a, b, c Sulphur is brittle

5 b Platinum is a noble metal

6 b 4 to 8 electrons are present in outermost shell

7 b Valency of SO3 is 6

8 b Non metals form covalent bond with other non metals

9 c Oxy acids are formed

10 a, d Non metals have high electro negativity and low electro positivity



11 b Non metals tensile strength is low

12 d Alloying is done to increase overall properties

13 d Non-metals are not reacting with water

14 b Under high temperature non metals reacting with metals to form oxides

15 a Oxides of carbon are acidic in nature

16 a, b, c Coinage metals are copper, gold and zinc

1 c Liquid metal is mercury

2 a Sodium can be cut with knife

3 a Metals are good conductors of heat and electricity

4 a Mercury is poor conductor of electricity

Exercise 5 Paragraph Type Questions

Level 3 Exercise 6 Questions from/for Olympiads

1 b Bauxite is an ore of aluminium

2 Pic is not there

3 a Galvanization is the process

4 c One and three is not feasible

5 c Magnentite is a carbonate ore of Mg

6 b Others are metals

7 c 93% of iron is present

8 a All ores are minerals

9 c Those elements are reactive

10 a H2 gas is evolved

11 b This is based on their reactivity strength

12 b Nickel is used for making boats

13 b Salt and water formed in this reaction

14 c Metals react with oxygen to form metal oxide

15 b Non metals applied on wounds

16 d Phosphorus is highly reactive

17 a Sulphur is used in vulcanization of rubber

18 c Aqua regia is 1 part HNO3+ 3 parts conc HCl

19 b Red colour of ruby is due to chromium oxide

20 b Nickel is used in preparation of vanspathi

Propel Academy

CHAPTER 2 COAL AND

PETROLEUM Chemistry


Serial No.


1 d Solid, gas and liquid fuels are available

2 c It never be poisonous

3 d We are using fuels for cooking

4 a We will get it continually

5 c Coal is a non-renewable source

6 a Coal formed from plants

7 d It consists of C, H and O

8 a Coal formed due to high temperature and pressure

9 c The process of conversion of vegetable matter called carbonization

10 a Coal used in thermal power station

11 b Coal formation is called carbonisation

1 b The process of destructive distillation of coal is carried out by heating coal at a high temperature

2 c This process is also called as pyrolysis

3 c Plastic is not formed in this process

4 b This is normally used for the preparation of paints

5 a Liquor means liquid or fluid



1 b Lignite is the lowest grade

2 d Highest amount of carbon in anthracite

3 c Natural gas obtained from this process

4 c Bituminous is a soft coal

5 d It has highest quality

6 b This type coal has shininess

7 c Nitrogen is not present in coal

8 d It has superior quality


Class VIII C2: Coal & Petroleum


6 d Coal tar not used for making coke

7 a It used as good reducing agent in the manufacturing of steel.

8 c Both gases are produced

9 d It is a mixture of hydrogen, methane and carbon monoxide

1 b The world's oldest running oil refinery, located in the northeast corner of India

2 b It is house hold variety

3 a Natural gas is an ideal fuel

4 d All these are ideal fuels

5 c Fuel means coal only we are using in nuclear power plant

6 a CO entered into our blood and bind with hemoglobin

7 a Biogas is a mixture of methane and CO2

8 c Coal is obtained from waste plant materials

9 d Crude oil contains all these

10 a That’s combustion

11 b LPG is not in the manufacture of chemical fertilizers

12 d Diesel has high volatility


1 b The unrefined form of petroleum is called crude oil or rock oil

2 c Petroleum was formed from the organisms living in the sea

3 a By drilling in the Earth’s crust and sinking pipes deep down in the rocks

4 b The process of separating the various components of petroleum from one another is known as the refining of petroleum

5 a Fractional distillation is a method

6 a 150-2500c kerosene obtained

7 b The residues are formed in 3500c

8 a Fractional distillation, crude oil heated in 4000c

9 c Kerosene used in jet

10 a In petrol, number of carbon atoms low


1 b Main constituent of natural gas methane

2 a It has a very high calorific value 50,000 kJ/kg

3 c Compressed natural gas

4 d Grass is not related with fuels

5 a Gas changes to liquid form




13 a Petrochemicals are the products

14 a Petroleum Conservation Research Association

1 b Crude oil is a fossil fuel

2 d Another name of petroleum is hydrocarbons

3 d The most common resources of energy used in automobiles is diesel

4 c Petroleum can be processed by fractional distillation

5 c Solid fuels leave more smoke and ash on burnings

6 c Coal is formed by carbonization

7 a Fuels combine with oxygen to produce heat and light

8 a Main constituent of gobar gas is methane

9 a Gas in lpg cylinders is liquefied by applying high pressure

10 b Coke

11 a,b,d Good fuel should be low cost, minimum pollution and readily available

1 a Petroleum is rock oil

2 b Crude petroleum is heated at 400oc to 500oc

3 c Different boiling points of each fraction

4 d Gasoline is used as fuel

Exercise 2 One or more than one correct answer

Exercise 3 Paragraph questions


1 a Coal and petroleum formed naturally

2 a It is used to obtain producer gas (CO + N2) by passing air over the red hot coke

3 b So we can use renewable source

4 d Anthracite is the highest rank coal

5 b Heating coal at 12700c

6 c Reason is false

7 b Natural gas can be stored under high pressure

8 b Methane is separated from hydrocarbons and hence natural gas is refined




1 a It the process related with coal formation

2 b Coke undergo destructive distillation

3 d Hydrocarbons obtained from cracking

4 c Refining is the process related with petroleum

1 d That is liquefied petroleum gas

2 a This type of coal used in paints

3 b Paraffin wax used in ointments

4 c Petrol is an aviation fuel

1 c Petroleum has very strong smell

2 a Natural gas occurs above petroleum oil

3 a It is very valuable oil

4 a These are the main constituents

5 c These days, bitumen, a petroleum product, is used in place of coal-tarfor metalling the roads

6 b, c, d These are not the properties

7 a, d Coal gas contains all these

8 b Electricity produced from tides

9 b, c, d Agricultural wastes are renewable source

10 a,c,d Ideal fuel cause minimum pollution

11 a Coal is a solid fuel

12 d Diamond occurs naturally

13 a Coal gas is not obtained

14 c LPG leakage is detected by ethyl mercaptan

15 b

16 b Methane is known as fire damp


Propel Academy

CHAPTER 3 ATOMIC AND

MOLECULAR MASS

Chemistry


Serial No.


1 a This is avagadro’s number

2 c Mole is the unit of measurement

3 d Isotope is the version of same element

4 d All are carbon isotopes

5 a 28.09 is the atomic mass of Si

6 c Specific heat of water is 1

1 a Half number due to isotope

2 a Relative atomic mass 12 of carbon

3 c Mass % of copper is 0.8882

4 c 3O3 relative atomic mass 180

5 b the ratio of the average mass of one atom of an element to one twelfth of the mass of an atom of carbon-12

6 c Molecular mass of Na2CO3. 10 H2O is 286

7 b 100.1151. KHCO3 is a white crystal at room temperature

8 a Molar mass of CaCO3 is 100.0869 g/mol.

9 b ChlorineCl 35.453263.888% CalciumCa 40.078136.112%

10 b 1 g = 1000 mg Molar mass of carbon dioxide (CO2) = 44 g mol-1 Given mass of CO2= 220 mg = 0 22 g Number of moles , 0.22/0.44=0.005

11 c Mass ratio C : H = 82.66 : 17.34 Divide by relative atomic masses to get the mole ratio Mole ratio C : H = 82.66/12.01 : 17.34/1.008 = 6.88 : 17.20 To get this as a 1:x ratio, divide both by the smaller of the two Mole ratio C : H = 6.88/6.88 : 17.20/6.88 = 1 : 2.5 To get this as a whole number ratio, multiply both by 2



1 a Molar mass of oxygen is 32

2 d It contain iron and oxygen

3 c Atomic mass of oxygen 16

4 b NaCl formula mass 58.5

5 a CaCl2 molar mass 110

6 b Mg3N2 is the formula

7 c 22.4 L is the molar volme of ideal gas


http://www.convertunits.com/element/Chlorine

http://www.convertunits.com/element/Calcium

Class VIII C3:Atomic & molecular mass


Mole ratio C : H = 2 : 5 Therefore, the empirical formula is C2H5

12 c The correct empirical formula C3H4F2 and then calculated the mass of this empirical formula to be 78 which is of the molecular mass and multiplied the formula by 2

1 d Molar mass of Zn 65.4

2 c Molar mass of water 18

3 a Molar mass of oxygen 32

4 b Molar mass of N2 28

1 d Formula of acetic acid CH3COOH

2 a Formula of ammonia NH3

3 c Formula of methane CH4

4 b Formula of ethane C2H6

1 d HCl – r

2 a H2SO4- p

3 c NH3 – s

4 b HNO3 - q

1 c CaCO3 – s

2 d C – p

3 a NaCl – r

4 b Sucrose – q

1 b H2O molecular mass is 18 u

2 c Molecular mass of C2H5OH= 2(12)+ 5(1)+16+1 = 46 u

1 b 2P + 3Cl2 -- 2PCl3

2 c 1NH3 + 3 Cl2 -- NCl3+ 3HCl

1 b Equations is always a balanced one

2 d Flourine atomic weight 18.9 u

3 b One mole =12g of Carbon

4 d HCl molecular mass is 35.5 u

5 b SI unit of molar mass is kg/mol

6 b Both statements are true

7 b Water is H2O




Class VIII C3:Atomic & molecular mass


8 a Aspirin is C9H8O4

9 b NaCl formula mass is 58.44 u

10 b Cholroform is CHCl3

1 c Structure of glucose and benzene are similar

2 d Empirical formula shows the whole number ratio

3 c SO3

4 a C 1.00 , H 2.643 It looks by inspection that multiplying by 3 should give whole numbers: C 3.00 , H 7.93 ~ 8 , Empirical formula is C3H8

5 b Na = 42.07/32 = 1.829 P = 18.89/31 = 0.609 O = 39.04/16 = 2.44 then divide each of you answers by the smallest: Na = 1.829/0.609 = 3 P = 0.609/0.609 = 1 O = 2.44/0.609 = 4 so the empirical formula is Na3PO4

6 b Styrene has 92.26% of Carbon and 7.74% of Hydrogen

7 a 14% hydrogen and 86% carbon

8 c We can’t divide the number of O

9 c Uranium has more than one isotope

10 b Nitrogen is a chemical element with symbol N and atomic number 7

1 b The compound butene has a molecular formula of C4H8

2 Question is incomplete

3 a Used in the study of crystalline solids

4 b 6.022x1023 particles

5 d Molar mass

6 a 6.022x1023 particles= 1 mole

7 b 1 mole = 65.38 g = 6.022 x 1023; 2.5 mole = 2.5 x 65.38 =2.5 x 6.022 x 1023= 1.51 x 1024 atoms

8 d All of the above

9 b Tin has 10 number of isotopes

10 a Relative atomic mass

11 d Atoms

12 c Given amount is 10 moles of water = 10 x 3 = 30 mole of atoms

13 b Coefficient of Hydrogen is 17

14 a 1KNO3 +H2SO4 -- HNO3 + KHSO4



Propel Academy

CHAPTER 4 CHEMICAL BONDING

Chemistry


Serial No.


1 c 5 valence electrons for nitrogen

2 a Covalent means sharing of electrons

3 a Lewis proposed Lewis dot formula

4 b Ther are 6 evalence electrons

5 c Ionic compounds possess high melting and boiling points

1 b Na has 11 electrons and Na+ has 10 electrons

2 a Valence of ion = no of positive or negative charges acquired by an atom

3 d NaBr is an electrovalent bond

4 a Chemical bond

5 b Cation is formed by losing an electron

6 b Electrostatic forces held cations and anions together

7 a H2 is covalent

8 b Diamond has 3 d covalent structure

9 b Each bond has 2 electrons and hence double bond has 4 electrons

10 c Nitrogen has triple bond between the atoms

11 b CaS has the highest melting point

12 b Potential energy decreases

13 a A covalent bond is formed when combining atoms share the electron pairs

14 c Both attractive and repulsive forces

15 a C2H2 is a covalent compound

16 a Bond formation is always exothermic

17 c It shares electrons

18 b Bond between y atoms is covalent

19 c X2Y is the compound



1 d these exist as gases or liquids of low boiling points

2 b Polar covalent bond is a type of covalent bond formed between two non-identical atoms

3 d soluble in non-polar solvents like benzene, carbon tetrachloride, ether

4 b sharing of two electron pairs is called a "double covalent bond


Class VIII C4:Chemical Bonding


20 d Al transfers three electrons to Nitrogen

1 a, b,c,d All can form covalent bond

2 c forming three covalent bonds, a so-called triple bond

3 d An oxygen atom can form two covalent bonds

4 a, b Molecules having single bond are H2, F2, Cl2

1 d It is a weak acid

2 a, c It forms ionic bond

3 a, c It forms covalent bond

4 a, d Na2SO4 is a salt of a strong acid(H2SO4) and strong base(NaOH)

1 a Strong metallic bond

2 b Weak metallic bond

1 b Non mobility of hydrated aluminium and chloride ions

2 a Mobility of hydrated aluminium and chloride ions

1 c Covalent bond sharing electrons

2 b It is made upof ions

3 b A bond formed by the equal contribution and equal sharing of electrons between two atoms or more atoms is known as covalent bond

4 b Elctrons gain substance is electronegative

5 a Nitrogen has 5 valence electrons

1 a,b, c, d by transfer of one or more electrons from one atom to another

2 a, d Argon is a noble gas

3 a, b, c Atoms can gain or lose more than one electron at a time

4 a, b, c, d All these have ionic bond

5 a,c, d covalent bondsseem to be weaker than those with ionic bonds

6 b Graphite is a good conductor

7 d Molecules having single bond are H2, F2, Cl2

8 a, b, c Ionic compounds possess high melting and boiling points

9 c Bonds have both attraction andrepulsion

10 a Helium ; Argon have eight electrons in their valence shells

Exercise 2 Matrix Type




Class VIII C4:Chemical Bonding


11 c They want to attain stability

12 d All of these

1 d Noble gases

2 b Force of attraction overcome force of repulsion

3 a Valence electrons in an atom

4 b Valency of nitrogen is 3

5 c Ionic substances are soluble in water

6 a Have similar electronegativity

7 b Covalencies are 1, 1, 2, 3

8 d Maximum no of electrons is BCl3

9 d They undergo chemical reaction quickly

10 d All of these

11 d All of these

12 a,b,c Ionic properties do not exhibit space isomerism

13 c High melting point, high boiling point

14 c Conductors in solid state

15 a Higher the temp, more the solubility


Propel Academy

CHAPTER 5 CARBON AND ITS

COMPOUNDS

Chemistry


Serial No.


1 d All these are allotropic forms of carbon

2 d It has no free electrons to conduct electric current

3 a Double bond is formed by the sharing of two pairs of electrons of the valence shell. Example: Oxygen molecule (O = O)

4 c Methane is formed by non-polar covalent bonding, CO2 contains covalent

5 b Carbon dioxide demonstrating adouble bond

6 c Covalent means sharing of electrons

7 d It has no free electrons to conduct electric current

1 a The general formula for an alkane is: CnH2n+2

2 b Alkyne general formula CnH2n-2

3 d German chemist Friedrich Wöhler first synthesized urea in 1828

4 a Minimum 4 carbon atoms

5 c This is the name of ethanol

1 b Power alcohol generally has 80% petrol and 20% ethanol

2 b Less oxygen means less combustion leading to unburnt carbon particles giving utensils black colour at bottom

3 c Rectified spirit is 95% ethanol

4 a or b Ethanol

5 c Acetic acid is the product

6 c Secondary alcohols have an -OH functional group

7 b Six C-H bonds are there

8 d Aall these are properties of carbon

9 a A saturated hydrocarbon (Alkane) would have the general formula CnH(2n+2)

10 c Acyclic or open chain compounds: These contain alkanes, alkenes, alkynes

11 c Phenol, also known as carbolic acid, is an aromatic organic compoundwith the molecular formula C6H5OH

12 a All others have general formula CnH2n+2




https://en.wikipedia.org/wiki/Friedrich_W%C3%B6hler

Class VIII C5:Carbon & its compounds


1 d Diamond is abrasive

2 c Water gas is a synthesis gas, containing carbon monoxide and hydrogen

3 b Producer gas, mixture of flammable gases (principally carbon monoxide and hydrogen

4 a Graphite is used as a lubricant

1 b Increased amount cause global warming

2 a It binds with haemoglobin

3 d Natural gas produced from fossil fuels

4 c Dry ice is solid CO2

1 b They contain sulphur and nitrogen

2 c It produces less amount of CO2

1 a Due to excitement and de-excitement of electrons

2 b Due to total internal reflection of light

1 a Carbon has a lot of special properties

2 a Diamonds get their brilliance from three things: reflection, refraction and dispersion

3 a Graphite is another form of carbon

4 b Oxidizing agents give oxygen to another substance

5 c Hydro carbon has only hydrogen and carbon

1 d Have weak forces of attraction between layers

2 b Diamond has an extremely low thermal expansion, is chemically inert with respect to most acids and alkalis

3 a, c it has a formula C2H4 (ethylene) it obviously has a double bond

4 b, c naphthalene is classified as a benzenoid polycyclic aromatic hydrocarbon

5 a, b, c, d

Cellulose, which makes up the walls of plant cells, contains carbon

6 a, b, c All these are properties of carbon

7 a Allotropes are differentstructural forms of the same element

8 a,b, c, d

Carbon nanotubes (CNTs) are allotropes of carbon

9 c,d Isoprene (C5H8)contains two double bonds and is therefore even more reactive

10 c, d Theelectron configuration of a carbon atom is 1s22s22p2

11 a, b, c alcohol is not a hydrocarbon



Level 2 Exercise 4 Assertion and reason


Class VIII C5:Carbon & its compounds


12 d carbon is also the most important element plastic

13 b, c, d All these are allotropes

14 d Carbon arranged as tetrahedral

15 d All these contain carbon

16 d Dry ice is frozen oxygen gas is wrong statement

1 b The four valence electrons of each carbon atom participate in the formation of very strong covalent bonds

2 b The most reactive form of carbon is charcoal

3 c Electric conductor

4 a CO2 is the option

5 d Lead pencil has graphite

6 a Incomplete combustion gives CO

7 b Carbon dioxide gives tangy taste to soft drinks

8 d Different layers in graphite are held together by vander wals’s forces

9 b,d Main constituent of LPG are propane and butane

10 c Good fuel has high calorific value

11 a Ethane do not contain multiple bonds

12 c Charcoal is the answer

13 d Diamond has no free electrons


Propel Academy

CHAPTER 1 WHAT IS INSIDE

THE ATOM

Chemistry


Serial No.


1 b Protons present inside the nucleus

2 a Protons are heavier than electrons

3 b - Particles are made up of two protons and two neutrons and are He nuclei

4 b It is based on atom

5 b This is the mass of proton

6 b He used gold foil for his experiment

7 b Hydrogen represents proton

1 b Electron Capacity = 2n2

2 c It is the diameter of a nucleus

3 c P can accommodate 6 electrons

4 a We are using capital letters

5 c A neutron is represented as n0

6 a We are using s, p, d and f

7 c We can using this formula, 2n2 to find out number of electrons

8 c 14 is the maximum number of electrons

1 a 27 protons and neutrons

2 c Maximum 32 electrons

3 b The atoms of different elements with different atomic numbers

4 a Ion or atom or molecule which has the same number of electrons

1 a Any element in group 1 has just one valence electron

2 b Neon lies in 8th column, so it has 8 valence electrons

3 b This is the isotone

4 b Isotope has different number of neutron





Class IX C1:What is inside an atom


5 a 1s22s22p63s23p64s23d3

6 a Starting from the right, at group 1A, which is the column that Hydrogen is at the top of, and also includes Sodium. All elements in this group have 1 valence electron

7 b Neutron is neutral in charge

8 b 2 paired and 2 unpaired electrons in p-orbital

9 d Atoms vary in size according to the element, but their diameters are of the order of 1 × 10-8 cm=10-10 m

10 c Another isotope of carbon, which seems to be the one you are referencing, has 6 protons, 8 neutrons, and 6 electrons

11 b The maximum number of electrons which can be accommodated in any energylevel of the atom is given by 2n 2 (where n is the number of that energy level)

12 a Uranium used as nuclear fuel

1 c Atomic theory proposed by John Dalton

2 d Electron was discovered by J. J. Thomson in 1897

3 b Proton discovered byy Goldstein

4 a Paramanu term intrroduced by Maharishi

1 c Hydrogen 1S1

2 d Boron 1S22S22P1

3 b Helium 1S2

4 a Carbon 1S22S22P2

1 c Electron mass is lower than proton mass

2 b Neutron has no charge

3 b Atom is mostly empty

4 Question incorrect

5 d Na has 11 electrons, Na+ has 10 electrons

6 a The more the shell no, more the energy

1 b, c, d Isoelectronic refers to two atoms, ions or molecules that have the same electronic structure and same number of valence electrons

2 a Isotope has similar chemical properties

3 a, d L shell of phosphorus has 8 electrons


Level 2 Exercise 3 Assertion and reason


Class IX C1:What is inside an atom


4 a, c Electron is in the orbits

5 a,b,c,d all atoms of chlorine contain 17 protons, chlorine-35 and chlorine-37 differ in the number of neutrons each one has.

6 a,b All isotopes of an element have the same number of valence electrons

7 b It has one negative charge

8 a,b, c a distinct kind of atom or nucleus characterized by a specific number of protons and neutrons

9 a, b, c, d All these are shells

10 c 1s^2 2s^2 2p^6 3s^2 3p^6 4s^13d^5

11 d These are called nuceons

12 c It contains 11 protons and 12 neutrons

13 d James Chadwick discovered neutron

14 d The maximum number of electrons that can be filled in a valence shell is eight

Exercise 5: Linked Data Questions

1 b 1:4 is the correct option

2 d Energies are in the ratio 4:1

1 d Valence shell has 10 electrons

2 c Valence shell no is 4 for atomic number 38


1 a There are 24 electrons

2 a The diameter of the nucleus is in the range of 1.75 fm (1.75×10−15m)

3 c 11 protons and 11 electrons

4 a The question is Fe2+ has how many unpaired electrons. Fe2+ =[Ar]4s03d6

5 c Nucleus has 25 protons and 30 neutrons

6 d One molecule of oxygen has 16 electrons

7 a Isotopes

8 b ii and iii postulates are true

9 c Dalton’s atomic theory

10 b,c Positively charged nucleus at the centre of atom

11 b Given elements are isobars

12 d Atomic number 9 and mass number 19

13 c Atomic number of the element is 13

14 a K, L has least energy difference

15 c mvr=nh/2

16 d Mass number = 23

Propel Academy

CHAPTER 2 PERIODIC TABLE

Chemistry


Serial No.


1 b According to increasing atomic masses

2 a Ge found place later

3 c Modern periodic table has 18 vertical columns known as groups

4 c Metalloids

5 c E2O3 is oxide of Eka Aluminium

6 a Boron atomic weight is corrected

7 d Noble gases are in VIII A

8 d General electron configuration of d block elements is (n-1)d1-10ns1-2

Serial No.


1 a It complete outer shell

2 b The p-block comprises of elements of group 13 to 18

3 b Each period ends with a noble gas having ns2np6

configuration

4 c IV A contain lead

5 b The non metallic nature of boron is due to its smallsize and high ionisation energy

6 a the atomic radius increases as the group and energy levels increase

7 c All these are rare

8 b K easily lose electrons

1 b C,Si, Pb, Sn comprises IVA

2 c These group contain semi metals

3 d It is more reactive element

4 a Bi is the last element in group 15 so it is the most metallic

5 a Electronegativity decreases

6 a Most of the time elements in the same group have the same number of valence electrons.

7 c Valence is constant in groups

8 b Group 14




Class IX C2: Periodic Table


9 b Period 2 has k and l shells. Outermost shell is L

10 b F< O < C < Be < Li

1 a Mendeleev’s periodic table is based on Atomic mass.

2 a The law of octave was proposed by Newlands

3 b Al, Si, P, S are belongs to same period

4 b Mendeleev’s arranged 63 elements

5 c Limitation: Electronic configuration resembles of hydrogen and alkali metals .No fixed position for Hydrogen

6 a Newland octaves rule applicable only up to Calcium

7 b Horizontal rows is known as Periods while Vertical columns are known as Groups

8 c Triads are known as a set of three elements having same chemical property

9 a Modern periodic table stated by Mosley

10 c No. of groups 18 & No. of periods 7

11 a Na(11) and K(19) are belongs to same group

12 d Atomic number is 35

13 c I A group element is K

1 a Noble gases have stable electron configuration

2 d Alkali metals can form OH- ions

3 b Modern periodic table is based on atomic numbers

4 b Largest division of periodic chart would be the metals

5 c Boron has less size than Beryllium

6 c Atomic numbers of isotopes are same

7 b Largest atomic size has least ionization potential

8 b First period is the shortest and sixth period is the largest

1 d Highly reactive metals

2 c Heavy metals

3 b Lanthanides

4 a Zero group elements

1 d Highest electron affinity

2 c Oxidation state -1

3 a Highest first IP

4 b Radio active metal






1 d Metallic character decreases as we move from left to right

2 c Non metallic character increases from left to right across a period

3 b Oxidizing character of elements down a group

1 c N, O, F, Na, mg and Al

2 d

3 a

1 a, b, c Ratio is not a periodic property

2 a, b, c This all will show diaginal relation

3 a, b, c The factors that affect ionisation energy are size of the atom, charge of nucleus and screening effect of inner electrons.

4 a, d (IP1) of N > (IP1) of O

Configuration of N (7) = 1s22s2 2p3

Configuration of O (8) = 1s22s22p4 N is half filled that’s why it requires comparative high

energy to remove electron from it orbit than O. (IP)2 Li > (IP)2 of Ne

(IP)2 means second ionisation potential, Configuration of

Li+ = 1s2

Configuration of Ne+ = 1s22s22p5, Li+ is fully filled

5 a, b, c, d All forms amphoteric oxide

6 c Periods indicates principle quantum no

7 b Refractive index is not a periodic property

8 a,b,d These are the anomalous pairs

9 d Na acts as best reducing agent

10 d 7th period is the incomplete period

11 a,b,c

1 b It Recur after certain regular interval

2 a Diagonal relationship seen between 2nd and 3rd period

3 a Elements of d block are Transition elements & f block elements are known as inner transition element

4 a Elements of 1st group is known as Alkali metal Elements of 2nd group is known as Alkaline earth metal

5 a In all the 3 case an s– electron in the unpaired state is to be removed. In the case of Cu a 4s electron is to be removed which is closer to the nucleus than the 5s electron of Ag

Exercise 4 Linked Comprehension type


LEVEL 3 Exercise 6 Questions from/for Olympiads & NTSE



6 d As the polarising power is increasing so is the order M+1< M+2< M+3< M+4

7 d Both are amphoteric

8 b Both have nearly the same size

9 d K+ has 18 e-, Ca2+ has 18 e- and Ne has 10 e-

10 c d5<P3<d10<p6

11 a Li<Be<Mg

12 c Phosphorous has half filled electronic configuration

13 c Electron addition is easier in O2-

14 a Barium in presence of oxygen gives BaO and BaO2

15 b 6th period has 32 elements

16 a D block has only metals

17 A,c Given options don’t follow Dobereiner’s law

18 b Second element has 2 valence electrons

19 c (n-1)d shell and ns sub shell has less energy difference

20 a I1 has least value

Propel Academy

CHAPTER 3 CHEMICAL BONDING

Chemistry


Serial No.


1 a Attain 8 electrons in outer shell

2 b Valence electrons

3 c Only dots

4 b Electron deficient compounds don’t have 8 electrons

5 a Ionic compounds are solid

6 b Covalent bond

7 b Bad conductors of electricity

8 c Coordinate bond

9 d Covalent compounds not soluble in polar solvents like water

10 a Good conductor of electricity



1 b Overlapping of orbitals

2 a Larger atomic size

3 b Covalent bond

4 a Energy is decreasing

5 a Ionization enthalpy

6 b NaCl>CaCl2> MgO

7 b Electron affinity

8 a Strongest bond is ionic


1 a Sigma bond

2 c Axial overlap of orbitals gives p-p

3 b s-s < s-p<p-p

4 a s-s> s-p> p-p

5 b Pie bond

6 a Sigma bond

7 a 8 sigma and 1 pie bond

8 a Covalent bond

Class IX C3:Chemical Bonding


1 d ClO2 is an exception to octet rule

2 b Negative ion

3 c

4 b

5 d BF3 doesnt follow octet rule

6 a A2B3

7 Question has no correct options

8 b Electrovalent and covalent compounds

9 c MgO has the highest melting point

10 d Fused LiCl would be less conducting than fused NaCl

11 b Electrovalent

12 d C6H12O6 will not conduct electricity

13 d Covalency is equal sharing of electrons takes place between 2 atoms

14 d Atoms of the same size

15 c Dative bond is present in BaCl2

16 c Covalent bond

17 b SiCl4 is non polar

18 c F is most electronegative

19 b V shape is seen in water molecule

20 c Nitrogen covalency is 3

1 c 3 bond pairs and 1 lone pair

2 b 2 bond pairs and 2 lone pairs

3 d 2 bond pairs and 4 lone pairs

4 a 4 bond pairs and no lone pairs

1 d Triple bond

2 a Covalent bond

3 b Ionic bond

4 c Octet configuration

1 a Number of valency electrons in nitrogen atom is 5

2 b Electronic theory of valency is known as chemical bond theory

3 c Iron is less metallic than potassium

4 d Atoms are most stable than molecules

5 d Metallic bond is non directional

6 b




Class IX C3:Chemical Bonding


1 a Nitrogen has triple bond

2 a Bond strength is very high

1 a Hydrogen bonding in water

2 a Higher electro negativity of oxygen than sulphur

1 b Lithium

2 a, b, d Lewis symbol of sodium is not Na

3 a,b,c

4 a They are hard solids

5 a,b,c

6 c Acceptor has zero valence electrons

7 a,b,c,d

8 a,b,d Pie bond is not formed by hybrid orbitals

9 a,b,d Ionic compound is electrostatic forces

10 a,c,d Ethyl Alcohol has not hydrogen bond

11 a Covalence of nitrogen is 3

12 b Potassium has the strongest metallic bond

13 b,c,d In polar compounds separation of charges takes place is true

14 a,b,c NH3 has no partial charge separation

15 b,c,d

16 c Ionic bond

1 a Chemical bond

2 a Valence electrons in an atom

3 d

4 a,b,d

5 d CaI2 is least ionic

6 b Ammonium nitrate contains all the three bonds

7 d KCl boils at high temperature

8 c CaO

9 c Soluble in polar solvents like water

10 b Chlorine is more covalent

11 Question has no correct options

12 c Aluminium looses 3 electrons

Exercise 4 Linked Data



Propel Academy

CHAPTER 4 ACIDS, BASES

AND SALTS Chemistry


Serial No


1 b Slaked lime is an alkali

2 a organic acids are weak acids

3 b Substances with sour taste called acids

4 a Grape contains tartaric acid

5 b It is soluble in water

6 b Hydrogen gas is liberated

7 a,b Salt and water

1 a pH=-[log4.5 – 3log10]= 3-0.653= 2.347

2 b Replaceable hydrogen atoms

3 a M(1.75)=0.25 x 6 ; m=0.0857, pH=-log0.0857 = 1.07

4 a Mono acids

5 a pH<1 has strong acids

1 b Salts are mostly solids

2 b They have high melting points and boiling points

3 a It is an acidic salt

4 b It is a basic salt

5 b Acid change the colour blue to red

6 b Just like acids and bases, solutions of salts in water conduct electricity

7 b Tooth pastes are basic in nature

8 c Salts

9 c NaCl is salt

10 b Antacids are Mg(OH)2

1 a CO2 is released





Class IX C4:Acids, Bases & salts


2 b Bleaching powder is CaOCl2

3 c Efflorescence

4 c Gypsum is CaSO4. 2H2O

5 c Bleaching powder on exposure to air liberates chlorine gas

Serial No


1 b Carbonic acid H2CO3 is weak acid and H2SO4, HCl, HNO3 are strong acids

2 b This one only react with acid

3 b Neutralisation reaction are always exothermic

Acid + Base salt + water

4 b F>Cl> Br> I (basic strength in decreasing order)

5 c for weak acid

HA (aq) ˆ ˆ †‡ ˆ ˆ H+(aq) + A(aq)

here [H+] = [A]

6 a H3PO4> H3PO3> H3PO2 (Acid strength in decreasing order) H2SO4> H2SO3 (Acid strength in decreasing order)

7 c Down the group acidic strength decrease HNO3> H3PO4> H3AsO4> H3SbO4 (acid strength in decreasing order)

8 c Acidic strength order ClOH>BrOH> IOH (electronegativity decreases)

9 c Bases are bitter in taste

10 b All alkalies are bases but all bases are not alkali. Water soluble bases are called alkalies.

11 B Methyl orange gives red colour with acid

12 a Its molarity is 4

1 b NaOH have one hydroxyl group hence monoacidic

2 c Al(OH)3 is diacidic.

3 a, d Al (OH)3 is amphoteric, act both as acid and base

4 c Ca(OH)2is triacidic

1 b Zn(OH)2 and Al(OH)3 are amphoteric

2 a, d NaOH, KOH, Ca(OH)2 are strong alkalies

3 b, d Zn(OH)2 and Al(OH)3 are amphoteric

4 a, d NaOH, KOH, Ca(OH)2 are strong alkalies





1 a NaOH is a strong alkali

2 a Cold milk has basic properties

3 c Non metallic oxides are only acidic in nature

4 d Plaster of paris is used as plaster by dentists

5 b Acids and bases react to give salt and water

6 a

1 a, c All sulphides are not soluble in water

2 a, b, c, d kw = [H+] [OH] = 10–12

pkw= log kw = log 10–12 = 12

At 250C for H2O

[H+] = [OH] so [H+] = 10–6

pH = log [H+]

= log 10–6 = 6

H2O is neutral here because [H+]

= [OH]

pH = 6.5 means basic solution

3 b, c Water soluble base is alkali

4 a, b, c, d All these react with HCl in one step

5 c, d This base does not turn blue litmus to red

6 d pH = –log[H+] 3 = –log[H+] so, [H+] = 10–3 M Again pH = 6 so, Similarly [H+] = 10–6 M if 10–3 M solution is diluted 1000 times it conc. becomes 10–6 M.

7 c Methyl orange change to yellow colour

8 c Acid soil curved by spraying slaked lime

9 c Alkaline soil curved by gypsum powder

10 a Mg(OH)2 and KOH can be used as antacid to neutralize HCl produced in stomach

1 b HCl H+ + Cl






0.01 0.01 M [H+] = 0.01 M = 10–2M

pH = log[H+] = log (10–2) = 2

2 a pH = log[H+]

5 = log [H+] [H+] = 10–5 M So [HCl] = 10–5 M

3 a Given [HCl] = 0.01 M [H+] = 10–2 M

After dilution [H+] = 2

41010

100

pH = log [H+]

= log (10–4) = 4

1 a pOH =9.56

2 b pH = 14 – pOH = 4.435

3 c pH and pOH is 14

1 a Test tube A is acidic

2 b Test tube B is basic

3 b pH > 7

1 a Methyl orange gives red color in acidic medium and yellow in basic medium

2 c Organic acid are weak acids and generally mineral acids are strong acids

3 a Ca(OH)2 + Cl2 CaOCl2 + H2O

4 a It is called dead burnt plaster

5 a CaCl2 is hygroscopic as it absorbs moisture from the air

6 b Efflorescence substance are hydrated crystalline salt which loss their crystalline water at ordinary temperature

7 c Acidity of NaOH, Cu(OH)2 and Fe(OH)3 are 1, 2, and 3 respectively

8 d all these are epsom salt

9 c Two or more crystalline forms are called polymorphs

10 a It is a neutral oxide

11 a Bleaching powder has oxidising properties

12 d It is a double salt

13 b Pb(OH)NO3 is a basic salt. It has one OH ion which can be replaceable

14 c It is used as fire extinguisher

15 c pH range is 7 to 7.8

16 d pH = 10

17 c Epsom salt is magnesium sulphate




18 a Formic acid and ammonium hydroxide

19 a pH=-log4.3x10-4=4 – log 4.3 = 4 – 0.633 = 3.367

20 a Orange

21 c Nature of salt is neutral

Propel Academy

CHAPTER 5 CARBON AND ITS

COMPOUNDS

Chemistry


Serial No.


1 d CO2 is not an allotrope

2 d Fullerenes were discovered by H.W. Kroto, R.F. Curl and R.E. Smalley in 1985

3 c Diamond naturally occurring allotrope

4 d Graphite is soft material

5 a Methane contains C and H

6 a It has different forms

7 b C arranged as hexagonal rings

8 c It has tetra valency

1 d There are four single bonds, and no lone electron pairs in the methane molecule

2 d Double bonds in saturated hydrocarbons is zero

3 a The difference in the molecular masses of any two adjacent homologous is 14u

4 a Vinegar contains acetic acid

5 b They are fatty acids

6 d Alkynes is CnH2n-2

7 b Propane is C3H8

1 b Soaps are sodium salts of carboxylic acids

2 a Photochemical

3 c Nickel is catalyst

4 b Oxidation method

5 d Isomerism

6 a Single bonds

1 d Liquid petroleum gas (LPG), kerosene, petrol, plastics are carbon compounds

2 a Allotropes existence of the same element in various physical forms

e.g. diamond and graphite





Class IX C5: Carbon & its compounds


3 a Diamond and graphite and fullerene are allotropes of carbon

4 d Because of diff properties

5 d Diamond has tetrahedral crystal arrangement

6 a Diamond is an allotrope of carbon

7 d Diamond, graphite and fullerene are crystalline form of carbon. While coke is amorphous

8 d Diamond is bad conductor because it not have free electrons. Graphite is good conductor of electricity

9 b Ethanoic acid

10 b Methane, carbon monoxide and water

11 C,d

12 a Urea is first organic substance made in laboratory

1 a Graphite is a non metal

2 b Carbon has alot of properties

3 d Pentane is C5H12

4 b Pentane has three chain isomers

5 b All saturated hydrocarbons are aliphatic hydrocarbons

6 d Alkene is c4H8

7 b

8 b Aromatic hydrocarbon is benzene C6H6

1 d Esterification reaction

2 a Addition reaction

3 b Substitution reaction

4 c Neutralisation reaction

1 c Alcohol

2 d Carboxylic acid

3 a Ketone

4 b Alkene

1 a Since B is an acidic which on heating with A in presence of a few drops of conc. H2SO4 gives a sweet smelling compound C, therefore C must be an ester and A must be an alcohol. Since A is an alcohol with MF C2H6O, it must be ethanol (CH3CH2OH)

2 d Since ethanol (A) on oxidation with K2Cr2O7/H2SO4 gives an acid (B), therefore, acid (B) must be ethanoic acid.

3 d If A is ethanol and B is ethanoic acid then C must be ethyl ethanoate.

4 d Esterification reaction

Exercise 2 Assersion and Reason



Class IX C5: Carbon & its compounds


5 a Oxidation reaction

1 a, c Carbon structural with these two

2 a, b, c These three have sigma and pi bond

3 a, b, c Hese have double bond

4 b, c Benzene and naphthalene are aromatic

5 a, b, c, d All these contain bond

6 a CNG and LPG are hydrocarbon

7 c alkaneCnH2n + 2 ,alkene CnH2n, Alkyne CnH2n- 2

8 b Cyclohexane, Butane and Isobutane are saturated hydrocarbon. Benzene are unsaturated hydrocarbon

9 a Ethene, Benzene and ethyne contain multiple bond

10 c Homologue have – CH2 difference

ethane (C2H6) + CH2 C3H8 (propane)

11 c Ethyl Ethanoate is Ester

12 a,c,d 1 mole of ethyne on complete combustion gives 4 moles of CO2 and 2 moles of H2O

13 b,c,d Option A is homologous series

1 d Ionic bond formed by complete transfer of electron while covalent bond Formed by mutual sharing of electron. It is due to 4 valence electrons

2 a Alkynes have the shortest bond length

3 b Ethanol is basic in nature

4 a

5 c Ethene produced when ethanol is heated with excess of con H2SO4 at 443 k

6 a Vinegar has acetic acid

7 b Propyl Ethanoate

8 b

9 b Alkyne has triple bond i.e C3H4

10 b General formula of alcohols is CnH2n+1OH

11 d Propane has 8 C-H bonds

12 a Urea is first lab made organic substance

13 c Napthalene is not hydrocarbon

14 a Butane and Iso butane have the same molecular formula

15 b Saponification means alkaline hydrolysis of ester

16 a Soap is C18H37COONa

17 b Detergents do not precipitate in hard water

18 b Degradation of organic wastes in absence of air gives methane, hydrogen, nitrogen and carbon dioxides

19 d Magnesium oxide

20 c Benzene



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CHEMISTRY SOLUTIONS GRADE VI, VII, VIII & IX ALL CHAPTERS