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SECTION - I (40 marks)Compulsory : Attempt all questions from this section.

Question 1.(a) State the terms defined in the following:(i) The number of electrons donated or accepted by the valence shell of an

atom of an element so as to achieve stable electronic configuration.(ii) The rocky impurities including silica, mud etc. associated with the ore.(iii) The number of hydrogen ions which can be produced per molecule of the

acid in aqueous solution.(iv) Deposition of reddish brown coating on iron in moist air.(v) The number of atoms present in one molecule of that element.

(b) Give the balanced chemical equations for the following :(i) Dilute nitric acid is added to zinc metal.(ii) Calcium nitrate with sodium hydroxide.(iii) Steam is passed over red hot iron.(iv) Sodium thiosulphate reacts with dilute hydrochloric acid.(v) Sal ammoniac and slaked lime.

(c) State one observation for each of the following :(i) Hydrogen Chloride gas is poured in a gas jar containing a burning candle.(ii) Washing soda crystals are exposed to air.(iii) Concentrated sulphuric acid is added to sugar crystals.(iv) Ethene is treated with bromine water.(v) Sodium hydroxide solution is added to lead (II) nitrate in limited quantity.

(d) Give reasons for the following :(i) In the laboratory preparation of methane sodalime is used in preference to

sodium hydroxide.(ii) NaCl is preferred metallic chloride for the preparation of HCl.(iii) In extraction of aluminium by electrolysis, it is necessary to renew the

anode periodically.(iv) Liquid ammonia is used as a refrigerant in ice plants.(v) Electrolysis of molten lead bromide is considered a redox reaction.

(e) Give the structural formula for the following :(i) 2 - methyl propane(ii) But-2-ene(iii) 2-methyl propan -1-ol(iv) Ethanone(v) Ethanoic acid

(f) For parts (i)-(x), select the correct answers from the choices, A, B, C, D givenbelow. Write down only the letter corresponding to the correct answer forexample (xi)-R

(i) The elements of group 3 to 12 are known as

[5]

[5]

[5]

[5]

[5]

[10]

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(A) Transition elements(B) Normal elements(C) Bridge elements(D) None of these

(ii) An aqueous solution of potassium chloride is(A) Acidic(B) Neutral(C) Amphoteric(D) Alkaline

(iii) The composition of duralumin is(A) Al, Cu, Mg, Mn(B) Al, Mg, Ni(C) Al, Cu, Zn(D) Al, Cu, Mg

(iv) Aqua regia is a mixture of(A) 1part conc. HCl & 3 parts conc. HNO3(B) 3 parts conc. HCl & 1 part conc. HNO3(C) 3 parts dil HCl & 1 part dil HNO3(D) 1 part dil HCl & 3 parts dil HNO3

(v) Dissolution of ammonia in water produces(A) Hydronium ion as the positive ion(B) Hydroxyl ion as the negative ion(C) Hydrogen ion as the positive ion(D) None of these

(vi) When a metal atom becomes an ion(A) It loses electrons & is reduced(B) It gains electrons & is reduced(C) It gains electrons & is oxidized(D) It loses electron & is oxidized

(vii) The anhydride of sulphuric acid is(A) Sulphur dioxide.(B) Sulphur trioxide.(C) Amphoteric oxide.(D) Basic oxide.

(viii) Carbon dioxide & sulphur dioxide gas can be distinguished by using(A) Lime water(B) phenolphthalein(C) acidified potassium dichromate solution(D) moist blue litmus paper

(ix) The mixture of gases used in a blow pipe flame used for welding purpose is(A) Hydrogen & acetylene(B) Oxygen & ethane(C) Oxygen & acetylene(D) Oxygen & ethylene

(x) A white amorphous powder which on heating gives a colourless, odourlessgas which turns lime water milky and the residue obtained is yellow whenhot and white when cold is(A) Zn(NO3)2(B) PbCO3(C) ZnCO3(D) Na2CO3

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(g) Solve the following numericals :(i) What volume of oxygen would be required to burn completely 800 ml of

acetylene? (C = 12, H =1)(ii) State Gay-Lussac’s law of combining volumes.(iii) Calculate the mass percentage of each element present in water molecule.

[Atomic mass : H = 1, O = 16]

SECTION - II(Attempt any four questions)

Question 2.(a) Give the balanced chemical equation for the following conversions of A, B, C

& D

(b) Elements X, Y, Z have atomic numbers 11, 14, 9 respectively, with the giveninformation answer the following questions. Which of the following elements:

(i) Is the most electronegative element.(ii) Is a metalloid?(iii) Has the largest atomic size.

(c) Give a chemical test to distinguish between the following salt solutions(i) Lead nitrate & Zinc nitrate.(ii) Calcium chloride & Copper (II) chloride.(iii) Zinc sulphate & Zinc chloride.

Question 3.(a) For each substance listed below, explain its significance in the extraction of

aluminium(i) Graphite (ii) Sodium hydroxide(iii) Cryolite

(b) With reference to the diagram given below, answer the following questions:

[5]

[4]

[3]

[3]

[3]

[3]

(NH4)2SO4

A

NH4Cl NH4OH D BNH3

C

NCl3

Zinc nitrate +Iron (II)Sulphate solution

Conc. Sulphuric acid

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(i) What do you observe when freshly prepared ferrous sulphate solution ismixed with zinc nitrate solution and conc. Sulphuric acid is added to themixture.

(ii) Name the nitrates which do not respond to the above test.(iii) Why the nitrates in above question (ii) do not respond to this test.

(c) The following question refers to the periodic table.(i) What is the common feature of the electronic configuration of the elements

in group 17 or VIIA.(ii) Explain why, the properties of the elements are repeated after 2, 8, 18, 32

elements in the periodic table.(iii) What happens to the atomic size of elements moving from left to right in a

period.

(d) State one property of chlorine which agrees with it being a covalent compound.

Question 4.(a) A chemical compound is found to have the following percentage composition :

C = 19.5%, Fe = 15.2%, N = 22.8% and K = 42.5%. Calculate the empiricalformula of the compound. What will be the molecular formula of the compoundif its molecular mass is 368 amu.

(b) By drawing an electron dot diagram, show the lone pair effect leading to theformation of ammonium ion from ammonia gas and hydrogen ion.

(c) State the method mentioned below in the bracket for the preparation of thefollowing salts.(Direct combination, titration, Carbonate + acid, Double decomposition)

(i) Calcium carbonate(ii) Ammonium sulphate(iii) Iron (III) Chloride(iv) Lead nitrate

Question 5.(a) The diagram given below represents the laboratory preparation of acetylene,

with reference to it answer the following questions :

(i) Write the balanced chemical equation for it.(ii) State the method of collection of the above gas.(iii) Mention the impurities present in the gas.(iv) State the final product when Chlorine is passed into a solution of acetylene

in an inert solvent at room temperature.

[3]

[1]

[4]

[2]

[4]

[4]

water

calciumcarbide

acetylene

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(b) Acid and alkalis ionize in aqueous solution.(i) What ion is always present in an aqueous solution of an acid?(ii) What ion is always present in an aqueous solution of an alkali?(iii) The pH value of pure water is 7. Compare the pH value of carbon dioxide &

ammonia solution with that of pure water.

(c) State how the addition of the following compounds to hot concentrated sulphuricacid, serves as a test for the latter.(i) copper (ii) Sodium chloride

(d) Define roasting.

Question 6.(a) ‘P’ is an element in the form of a powder, ‘P’ burns in oxygen and the product is

soluble in water. The solution is tested with litmus. Write down only the wordwhich will correctly complete each of the following sentences.

(i) If ‘P’ is a metal then the litmus will turn __________.(ii) If ‘P’ is a non metal then the litmus will turn _________.(iii) If ‘P’ is a reactive metal then _______ will be evolved when ‘P’ reacts with

dilute Hydrochloric acid.(iv) If ‘P’ is a non-metal it will not conduct electricity, unless it is carbon in the

form of _________.

(b) With reference to electrolysis of copper (II) sulphate, answer the followingquestions :

(i) Name the product at both the electrodes using platinum electrodes.(ii) Write the anode reaction when platinum electrode is used.(iii) What difference in the products of electrolysis would be observed if copper

electrodes were used.(iv) State why the blue colour of aqueous copper (II) sulphate solution remains

unchanged during electrolysis of aqueous CuSO4 using copper electrodes.

(c) Calculate : (i) vapour density (ii) atomicity of chlorine if 35.5 g of it occupies a volume of 11.2 L

at STP.

Question 7.(a) Answer the following with respect to the property exhibited by the following

compounds.(i) concentrated sulphuric acid which allows it to be used in the preparation

of hydrogen chloride & nitiric acid.(ii) aluminium in thermite welding.(iii) concentrated nitric acid when it reacts with sulphur.(iv) hydrogen chloride when it is collected by downward delivery

(upward displacement).(v) acetic acid used in rubber industry.(b) Name the gas evolved when the following reacts with dilute hydrochloric acid(i) Sodium bisulphite(ii) Potassium carbonate(iii) Iron (II) sulphide(c) Write the molecular formula of the third member of the homologous series of

carbon compounds with general formula CnH2n + 1OH.(d) Name a nitrate which gives off oxygen as the only gas on heating.

[3]

[2]

[1]

[4]

[4]

[2]

[5]

[3]

[1]

[1]

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