Chemistry Dpp

APEX INSTITUTE FOR IIT-JEE |62-NITIKHAND-III, INDIRAPURAM, GZB |1204901457, 9910817866, 9990495952

CLASS : XI DATE : 01-02/05/2012 DPP. NO.-1

Question No. 1 to 3(3 questions)

(i) P + C (carbon) + Cl2 —→ Q + CO ↑ (ii) Q + H2O —→ R + HCl

(iii) BN + H2O —→ R + NH3 ↑ (iv) Q + LiAlH4 —→ S + LiCl + AlCl3

(v) S + H2O —→ R + H2↑ (vi) S + NaH —→ T

(P, Q, R, S & T do not represent their chemical symbols)

Q.1 Compound Q has

I. zero dipole moment II. A planar trigonal structure

III. An electron deficient compound IV. A Lewis base

Choose the correct code:

(A) I, IV (B) I, III, IV (C*) I, II, III (D) I, II, III, IV

Q.2 Compound T is used as a/an

(A) Oxidising Agent (B) Complexing Agent (C) Bleaching Agent (D*) Reducing Agent

Q.3 Compound S is

I. An odd-e– compound II. (2c – 3e–) compound

III. An electron deficient compound IV. A sp2 hybridized compound

Choose the correct code:

(A*) III (B) I, III (C) II, III, IV (D) I, II, IV

Question No. 4 to 6( 3 questions)

Acetic acid is added to the solution of sodium carbonate the gas evolved does not turn purple colour of

KMnO4 but turns lime water milky forming a compound (M) which becomes soluble by passing the

same gas in excess forming another compound (N). But same observation is not obtained with boric

acid

Q.4 Purple colour of KMnO4 has not changed because

(A) The gas has no oxidising property since central atom is with minimum oxidation state

(B*) the gas has no reducing property since the central atom is with maximum oxidation state

(C) The gas has no precipitation characteristics

(D) The gas precipitates CaCO3 from lime water


Q.5 The compound formed in the above sequence (M) and (N) are respectively

(A) Water soluble CaCO3 and water soluble Ca (HCO3)2

(B) Water insoluble CaCO3 and water insoluble Ca (HCO3)2

(C*) water insoluble CaCO3 and water soluble Ca (HCO3)2

(D) Water soluble CaCO3 and water insoluble Ca (HCO3)2

Q.6 The correct order of increasing acidity is

(A) Boric acid < Acetic acid < Carbonic acid (B) Acetic acid < Boric acid < Carbonic acid

(C) Carbonic acid < Acetic acid < Boric acid (D*) Boric acid < Carbonic acid < Acetic acid

Q.7 Unknown sample yellow sublimate yellow colour retained the compound is/are

(A) HgI2 (B) Ag2CO3 (C) SnS2 (D*) As2S3


1

2 3

4 12

5

13

6 7 15

8

14

9 17

16

10

11


ACROSS

3. Used for electrical conducting wire and too soft for most tools, early people learned

that this metal could be strengthened if it was

alloyed with tin or zinc.

4. The ancient Romans used this metal to make

water pipes and used as an antiknocking

agent in fuels.

5. Brass, a corrosion resistant alloy, is a mix of

copper and this metal.

8. The ancient Egyptians made black eye

make-up with this element.

9. A pale yellow material, this element can be

found near volcanoes and hot springs.

11. The cheapest of all metals, people have been

using this element for at least 5,000 years.

12. Quick lime, (CaO) when kept in open absorbs moisture from atmosphere and forms hydroxide

Ca(OH)2 . This means CaO is ––––––––.

13. Pure common salt is not, but common salt with impurities of MgCl2 is ________.

14. Gold can be drawn into thin wires. This shows gold is ___________

16. Substances which are good conductor of electricity are known as ________ .

17. Branch of chemistry in which study of carbon and its compounds is known as __________.

DOWN

1. This liquid metal has been found in 3,500 year old Egyptian tombs.

2. Commonly found as coal or soot.

6. Although known to the ancients, this metal was often confused with lead and tin.

7. A soft,valuable metal, its purity is measured in carats.

9. Frequently used in jewelry, this metal is the best conductor of heat and electricity.

10. Bronze, the first alloy created by people, is a mix of copper and this metal.

15. Alum (phitcari) on getting exposed gets converted to powder by loosing water of hydration by this

property.


ANSWER

ACROSS DOWN

3. Copper 1. Mercury

4. Lead 2. Carbon

5. Zinc 6. Bismuth

8. Antimony 7. Gold

9. Sulfur 9. Silver

11. Iron 10. Tin

12. Hygroscopic 15. Efflorescence

13. Deliquescent

14. Ductile.

16. Metal

17. Organic



Q.1 If water samples are taken from sea, rivers, clouds, lake or snow, they will be found to contain

Hydrogen and Oxygen in the approximate ratio of 1 : 8. This indicates the law of

(A) Multiple proportion (B*) Definite proportion

(C) Reciprocal proportions (D) None of these.

Q.2 The law of multiple proportion is illustrated by

(A*) Carbon monoxide and carbon dioxide (B) Potassium bromide and potassium chloride

(C) Water and heavy water (D) Calcium hydroxide and barium hydroxide.

Q.3 Hydrogen and oxygen combine to form H2O2 and H2O containing 5.93% and 11.2% hydrogen

respectively. The data illustrates :

(A) law of conservation of mass (B) law of constant proportion

(C) law of reciprocal proportions (D*) law of multiple proportion

Q.4 One of the following combinations illustrate law of reciprocal proportions

(A) N2O3, N2O4, N2O5 (B) NaCl, NaBr, NaI

(C*) CS2, CO2, SO2 (D) PH3, P2O3, P2O5

Q.5 H2S contains 5.88% H, H2O contains 11.11% H while SO2 contains 50% S. This illustrates the law

of:

(A) multiple proportions (B) constant proportions

(C) conservation of mass (D*) reciprocal proportions

Q.6 KCl exists in two isotopic form KCl35 and KCl37, these compound follow which law

(A) multiple proportions (B) constant proportions

(C) conservation of mass (D*) none of these.

Q.7 Weight of oxygen in Fe2O3 and FeO is in the simple ratio for the same amount of iron is

(A*) 3 : 2 (B) 1 : 2 (C) 2 : 1 (D) 3 : 1


Q.8 A sample of ammonium phosphate, (NH4)3 PO4, contains 3.18 mol of hydrogen atoms.The number

of moles of oxygen atoms in the sample is :

(A) 0.265 (B) 0.795 (C) 1.06 (D) 3.18

Q.9 1 gm-atom of nitrogen represents :

(A) 6.02 × 1023 N2 molecules (B) 22.4 lit. of N2 at N.T.P.

(C) 11.2 lit. of N2at N.T.P. (D) 28 g of nitrogen

Q.10 What mass of sodium chloride would be decomposed by 9.8 gm of sulphuric acid, if 12 gm of sodium

bisulphate and 2.75 gm of hydrogen chloride were produced in a reaction assuming that the law of

conservation of mass is true?[Assume none of the reactants are remaining] [Ans. 4.95 gm]

Q.11 In an experiment, 2.4 gm of iron oxide on reduction with hydrogen yield 1.68 gm of iron. In another

experiment 2.9 gm of iron oxide give 2.03 gm of iron on reduction with hydrogen. Show that the

above data illustrate the law of constant proportions.

Q.12 Zinc sulphate crystals contain 22.6% of zinc and 43.9% of water. Assuming the law of constant

proportions to be true, how much zinc should be used to produce 13.7 gm of zinc sulphate crystal and

how much water will they contain?

Q.13 Carbon combines with hydrogen to form three compounds A, B and C. The percentage of hydrogen in

A, B and C are 25, 14.3 and 7.7 respectively. Which law of chemical combination is illustrated?

[Ans. law of multiple

proportions]

Q.14 Illustrate the law of reciprocal proportions from the following data : KCl contains 52.0% potassium,

KI contains 23.6% potassium and ICl contains 78.2% iodine.



Q.1 4.6 × 1022 atoms of an element weigh 13.8 gm. The atomic mass of the element is :

(A) 120 (B*) 180 (C) 35.5 (D) 108

Q.2 The total number of moles in a closed beaker containing : (approx)

58.5 g of NaCl + 602.2 × 1020 molecules of O2 + 2 g of hydrogen gas + 22.4 litres of SO2 gas at NTP

+ 30 ltr of Cl2 at 0.0821 atm and 27°C.

(Assuming no reaction taking place) (R = 0.0821 L atm K–1 mol–1) [Ans.3.2]

Q.3 Calculate the % Na in a breakfast cereal which is advertised to contain 110 mg of sodium per

100 g of cereal. [Ans.0.11%]

Q.4 1.12L CO2 gas at S.T.P. + 0.44 g CO2 – 6.02×1021 molecules of CO2 = ________ moles of CO2.

[Ans.0.05]

Q.5 How many neutrons are present in 180 mL water at (i) 4°C & (ii) 127°C & 0.821 atm pressure.

[Ans: 80 NA, 0.036 NA]

Q.6 How many moles of C2H4O2 contains 6.02 × 1023 atoms of hydrogen? [Ans. 0.25]

Q.7

(a) How many atoms of oxygen are there in 1.00 mol of Ce2O3? (Ce mass number 140.)

(b) How many grams of Ce2O3 are in 0.400 mol of Ce2O3? [Ans. (a) 3NA, (b) 65.6 gm ]

Q.8 Which one of the following, if any, contains the greatest number of oxygen atoms? The greatest

number of molecules? 1.0 g of O atoms, 1.0 g of O2, or 1.0 g of ozone, O3. [Ans. same, O2]

Q.9 The true statement out of the following is /are

(A*) The mole is the amount of substance containing the same number of chemical units as there are

atoms in exactly 12 gms of 12C.


(B*) Avogadro’s number is the number of units in a mole.

(C*) The wt. of one gm-atom of an element means its atomic-weight in gms.

(D*) One gm-atom of each element contains the same number of atoms.

Q.10 An element (at. mass z) has a isotopic masses (z + 2) and (z – 1). Find the percentage abundance of

the heavier isotope. [Ans.33.3%]

Q.11 A mixture of gas ''X'' (mol. wt. 16) and gas Y (mol. wt. 28) in the mole ratio a : b has a mean

molecular weight 20. What would be mean molecular weight if the gases are mixed in the ratio b : a

under identical conditions (gases are non reacting).

(A*) 24 (B) 20 (C) 26 (D*) 40

Q.12 Density of dry air containing only N2 and O2 is 1.146 gm/lit at 740 mm and 300 K. What is %

composition of N2 by weight in the air.

(A) 78% (B) 82% (C) 73.47% (D) 72.42%

Q.13 The abundance of three isotopes of oxygen are as follows

% of O16 = 90%

% of O17 + % of O18 = 10%

Assume at. mass same as mass no. Find out % of O17 and O18, if the isotopic mass is 16.12.

[Ans.8, 2]

Q.14 It has been found by mass spectrometric analysis that in nature the relative abundances of the various

isotopic atoms of silicon are: 92.23% 28Si, 4.67% 29Si, and 3.10% 30Si. Calculate the atomic weight of

silicon from this information and from nuclidic masses. [Ans. 28.11]



Q.1 The empirical formula of a compound is CH. Its molecular weight is 78. The molecular formula of the

compound will be

(A) C2H2 (B) C3H3 (C) C4H4 (D*) C6H6

Q.2 On analysis, a certain compound was found to contain iodine and oxygen in the ratio of 254 gm of

iodine (at.mass 127) and 80 gm oxygen (at. mass 16). What is the formula of the compound.

(A) IO (B) I2O (C) I5O3 (D*) I2O5

Q.3 A given sample of pure compound contains 9.81 gm of Zn, 1.8 × 1023 atoms of chromium and 0.60

mol of oxygen atoms. What is the simplest formula.

(A) ZnCr2O7 (B*) ZnCr2O4 (C) ZnCrO4 (D) ZnCrO6

Q.4 ‘X’ is molecular substance containing 21 atoms of carbon per molecule. The weight % of C in ‘X’ is

50.4%. What is molecular weight of X.

(A) 400 amu (B) 176.5 amu (C) 287.6 amu (D*) 500 amu

Q.5 What is the empirical formula of a compound which contains 60.0% oxygen and 40.0% sulfur by

mass?

[Ans. SO3]

Q.6 A compound gave on analysis the following percent composition: K = 26.57%, Cr = 35.36%,

O = 38.07%. Derive the empirical formula of the compound. [Ans. K2Cr2O7]

Q.7 A 2 gm sample of Xenon reacts with fluorine. The mass of the compound produced is 3.158 gm. Find

empirical formula of the compound. [Xe –131.3 amu]; [F –19 amu] [Ans.XeF4]

Q.8 A drug marijuna owes its activity to tetrahydrocarbinol, which contains 70% as many C atoms as H

atoms and 15 times as many hydrogen atoms as oxygen atoms. The number of mole in a gm of it is

0.00318. Determine the molecular formula. [Ans.EF = C10.5H15O,

C21H30O2]


Q.9 A chloride of sulphur was found to have a molecular mass of 135. A 5.4 gm sample was also found to

contains 2.84 gm of chlorine. Deduce the molecular formula of the chloride.

[Ans.S2Cl2]

Q.10 One of the earliest methods for determining the molecular weight of proteins was based on chemical

analysis. A hemoglobin preparation was found to contain 0.335% iron.

(a) If the hemoglobin molecule contains one atom of iron, what is its molecular weight?

(b) If it contains 4 atoms of iron, what is its molecular weight?

Q.11 How much gas is evolved at STP on decomposing FeSO4 (7.6 g)

2FeSO4 (s) → Fe2O3(s) + SO2(g) + SO3(g)

What is the average molecular mass of gas. [Ans.1.12 litres, 72]



Q.1 The weight of 350 ml of diatomic gas at 0°C and 2 atm pressure is 1 gm. What is the atomic weight of

the gas ?

(A) 17.7 (B*) 15.99 (C) 27.7 (D) 38

Q.2 A mixture of CuO and Cu2O contain 88% Cu. What is the percentage of CuO present in the mixture?

(A) 91.35% (B*) 9.075% (C) 18.9% (D) 20%

Q.3 The vapour density of gas A is four times that of B. If molecular mass of B is M, then molecular mass

of A is

(A) M (B*) 4M (C) M/4 (D) 2M

Q.4 When 10 gm of Na2SO4. xH2O is heated to dryness 5.035 gm water vapour is produced, therefore the

value of x is

(A) 10 (B) 7 (C) 6 (D*) 8

Q.5 How many moles of potassium chlorate to be heated to produce 11.2 litre oxygen at NTP?

[KClO3 → KCl + O2]

(A) mol (B*) mol (C) mol (D) mol

Q.6 What is fertilizer rating of NH4NO3 (Fertilizer rating = N content by mass). Compare this with urea.

[Ans.35%]

Q.7 An element X forms oxides having percentages of X equal to 75%, 50% & 80%. Show that if proves

law of Multiple Proportions.

[Ans.Ratio]

Q.8 A compound contains 8% sulphur by mass. What will be its least molecular weight. [Ans.400]

Q.9 If pure Mohr’s salt crystals contain 15% iron and 30% water. How much Fe and how much water

should be taken to get 20 gm of its crystals. [ Ans.Fe = 3gm ; H2O = 6 gm ]


Q.10 How many kg of sodium and liquid chlorine can be obtained from 585 metric ton of salt ?

[Ans.230, 355 MT]

Q.11 A clay was partially dried and then contained 50% silica and 7% water. The original clay contained

12% water. What is the % of silica in the original sample? [Ans.47.31%]

Q.12 A sample of impure cuprite Cu2O contains 66.6% copper. What is the % of pure Cu2O by mass in the

sample. [Ans.75%]

Q.13 A certain compound was known to have a formula which could be represented as [PdCxHyNz]

(ClO4)2. Analysis showed that the compound contained 30.15% carbon and 5.06% hydrogen. When

converted to the corresponding thiocyanate, [PdCxHyNz](SCN)2, the analysis was 40.46% carbon

and 5.94% hydrogen. Calculate the values of x, y and z. [At. mass of Pd is 106] [Ans. x = 14, y =

28, z = 4]

Q.14 8 gm sulphur are burnt to form SO2 which is then oxidised by chlorine to sulphate. The solution is

now treated with BaCl2 solution. Find the amount of BaSO4 precipitated in mol. [Ans.0.25 mol]

Q.15 A piece of plumber’s solder weighing 3.0 gm was dissolved in dilute nitric acid, then treated with

dilute H2SO4. This precipitated the lead as PbSO4, which after washing and drying weighed 2.93gm.

The solution was then neutralized to precipitate stannic acid, which was decomposed by heating,

yielding 1.27 gm SnO2. What is the analysis of the solder. (Pb = 207.2 amu, Sn = 118.7 amu)

(A*) 66.7% Pb, 33.3% Sn (B) 33.3% Pb, 66.7% Sn

(C) 1 gm Pb, 2 gm Sn (D*) 2 gm Pb, 1 gm Sn



Q.1 12 mol of H2 and 11.2 mol of Cl2 are mixed and exploded. The composition by mol of mixture is

(A) 24 mol of HCl (B) 0.8 mol Cl2 and 20.8 mol HCl

(C*) 0.8 mol H2 & 22.4 mol HCl (D) 22.4 mol HCl

Q.2 Methyl benzoate is prepared by the reaction between benzoic acid and methanol, according to the

equation

C6H5COOH + CH3OH → C6H5COOCH3 + H2O

Benzoic acid Methanol Methyl benzoate

In an experiment 24.4 gm of benzoic acid were reacted with 70.0 mL of CH3OH. The density of

CH3OH is 0.79 g mL–1. The methyl benzoate produced had a mass of 21.6 g. What was the

percentage yield of product ?

(A) 91.7% (B*) 79.4% (C) 71.5% (D) 21.7%

Q.3 One mole of a mixture of CO and CO2 requires exactly 20 gram of NaOH in solution for complete

conversion of all the CO2 into Na2CO3. How many moles more of NaOH would it require for

conversion into Na2CO3 if the mixture (one mole) is completely oxidised to CO2:

(A) 0.2 (B) 0.5 (C) 0.4 (D*) 1.5

Q.4 How many ml of bromine will have the same mass as 12.5 ml of Hg if the densities of bromine and

Hg are 3.12 g/ml and 13.6 g/ml respectively :

(A*) 54.5 ml (B) 50.5 ml (C) 25.4 ml (D) 45.5 ml

Q.5 In an experiment 2.847 gm of pure MOCl3 was allowed to undergo a set of reactions as a result of

which all the Cl was converted to AgCl. The weight of AgCl was 7.2 gm. Find at. wt. of M.

[Ans.47.72]

Q.6 According to following reaction :

A + B O3 → A3O4 + B2O3

Find the number of moles of A3O4 produced if 1 mole of A is mixed with 1 mole of B O3.

[Ans.1/3]


Q.7 In an electric arc tube A, 140 g N2 is taken and in tube B, 20 g H2 is taken . When half the mass of

substance in tube A is transferred to B, reaction took place in B. After the reaction is complete, half of

the mass of substance in B is now transferred to A. Find out the final composition of gases in moles in

A and B.[no reversibility] [Ans.A (2.084 mol N2 ; 3.33 mol NH3) ; B ( 1.25 mol H2 ; 2.5 mol

NH3)]

Q.8 A 0.596 gm sample of a gaseous compound containing only B and H occupies 484 cm3 at STP. When

the compound is ignited in excess oxygen, all its hydrogen is recovered as 1.17 g H2O, and all the B is

left over as B2O3. What are the empirical formula and molecular formula, and the molecular weight

of B and H compound. What weight of B2O3 is produced by the combustion.

[Ans.(B2H6), 27.6 gm, 1.5 gm]

Q.9 Window glass is made by mixing soda ash , limestone & silica & then heating to 1500°C to drive off

CO2 from the mixture. The resultant glass contains 12% Na2O, 13% CaO & 75%. Silica by mass.

How much of each reactant would you start to prepare 0.35 kg of glass? [Ans.0.072 g, 0.081 g,

0.26 g]

Q.10 An unidentified bivalent metal M reacts with an unidentified halogen X to form an unknown

compound of halogen gas.When 1.12 g of it is heated, 0.72 g of MX is obtained along with 56 ml of halogen

gas at STP. Identify the metal.

[Ans.Cu]



Q.1 An evacuated glass bulb was weighed, then filled with oxygen and reweighed, the difference in weight

was 0.25 gm. The operation was repeated under identical conditions of (P, V, T) with unknown gas

“X”. The difference was 0.375 gm, find molecular weight. [Ans. Mwt.= 48]

Q.2 600 ml of a mixture of ozone and oxygen at STP weighs one gm. Calculate the volume of ozone at

STP in the mixture.

[Ans.200 ml]

Q.3 It is known that when 1 mole of H+ reacts with 1 mole of OH– x kJ of energy is released. Suppose

200 ml of 1 M XOH is mixed with 100 ml 2M H2Y [dibasic acid]. Calculate the total amount of

energy released. Assume that dissociation of the acid & base is complete & requires no energy. What

should be the volume of each solution that should be taken to obtain 100 ml of solution & maximum

release of energy. [Ans.

0.2x kJ; 80 ml, 20 ml]

Q.4 To a sample of an element X (at. wt. 70) element Y (at. wt. 120) is added as impurity. The ratio of

atoms of X to Y in the mixture is 1 : 10–7. How many gms of Y will be required for 100 gm of X for

this ratio.

[Ans.1.714×10–5 gm]

Q.5 Xenon is 0.0000087% by volume of the dry atmosphere. Express it in ppb (vol.) [Ans.87 ppb]

Q.6 A ‘w’ gm mixture of AgCl & AgBr undergoes a loss in wt. by 5% if it is exposed to excess

chlorination. Calculate the percentage composition of the mixture. [Ans. % AgBr = 21.12 % AgCl =

78.88% ]

Q.7 A certain compound has the molecular formula X4O6. If 10 gm of X4O6 has 5.72 g X, atomic mass

of X is

(A*) 32 amu (B) 37 amu (C) 42 amu (D) 98 amu

Q.8 If ratio of mole fraction of solute to solvent is unity, what would be % by wt. (concentration of solute)

(M solute = molecular mass of solute, M solvent = M molecular mass of solvent)


(A*) × 100 (B) 50%

(C) 66.67 % (D) × 100

Q.9 Molarity of pure ethanol (C2H5OH) with density d g/ml.

(A) (B) 25 d (C*) 21 d (D)

Q.10 On analysis of blood sample of a driver suspected of being drunk over than the permissible value, it

was obtained that 60 gm sample reacted with 30 ml of 8 M K2Cr2O7 (acidic soln.). If the permissible

value for the alcohol content in the blood is 1 % by mass, will the driver be prosecuted for drunken

drining. [Assume K2Cr2O7 reacts only with the alcohol present in blood.]

Reaction : 2K2Cr2O7 + 8H2SO4 + C2H5OH → 2Cr2(SO4)3 + 11H2O + 2K2SO4 + 2CO2

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Chemistry Dpp