MOLE CONCEPT

54 MOLE CONCEPT

APEX INSTITUTE - 62, Nitikhand-III, Indirapuram, Ghaziabad Ph.No.-+91-9910817866, 0120-4901457,website : www.apexiit.co.in/

Q.1 1 gram molecule of chlorine combines with a certain weight of a metal giving 111 g of itschloride. The same weight of the metal displaced 2 g of hydrogen from an acid. The atomicweight of the metal (assuming its valency to be 2) is :(A) 40 (B) 20 (C) 80 (D) none of these

Q.2 A solution of KMnO4 is reduced to MnO

2. The normality of solution is 0.6 N. The molarity is

(A) 1.8 M (B) 0.6 M (C) 0.2 M (D) 0.1 M

Q.3 9 gm of Al (at. Wt. = 27) will react completely with an acid to give :(A) one mole of H

2(B) one half mole of H

2

(C) one-third mole of H2

(D) none of these

Q.4 Number of moles of electrons taken up when 1 mole of NO3

– ions is reduced to 1 mole ofNH

2OH is :

(A) 2 (B) 4 (C) 5 (D) 6

Q.5 What volume of chlorine at STP is required to liberate all the iodine from 200 ml of 0.2 M KIsolution :(A) 896 ml (B) 448 ml (C) 224 ml (D) 672 ml

Q.6 5 ml of N HCl, 20 ml N/2 H2SO

4 and 30 ml of N/3 HNO

3 are mixed together and volume

made to 1 litre. The normality of resulting solution is :(A) N/5 (B) N/10 (C) N/20 (D) N/40

Q.7 Equivalent mass of Na2S

2O

3 in its reaction with I

2 is equal to :

(A) molar mass (B) molar mass/2 (C) molar mass/3 (D) molar mass/4

Q.8 A certain compound has the molecular formula X4O

6. If 10 gm of compound contains 5.62 g of X,

the atomic mass of X :(A) 32 amu (B) 37 amu (C) 42 amu (D) 48 amu

Q.9 The no. of mol. of the independent species present in one mole of potash alum(A) 32 (B)16 (C) 38 (D) 64

Q.10 How many gram of H3PO

4 would be needed to neutralise 100 gm of Mg (OH)

2 ?

(A) 66.7 gm (B) 252 gm (C) 112.6 gm (D) 168 gm

Q.11 Hardness of water sample is 300 ppm CaCO3. Hence its molarity is :

(A) 0.3 M (B) 0.030 M (C) 0.003 M (D) 0.0015 M

Q.12 What weight of CuSO4.5H

2O must be taken to make 0.5 litre of 0.01 M Cu2+ ions solution ?

(A) 12.45 gm (B) 1.245 gm (C) 6.24 gm (D) 100 gm

Q.13 Calculate the volume of CO2 produced by the combustion of 40 ml of acetone vapours in

presence of excess of oxygen(A) 12 ml (B) 1.20 ml (C) 120 ml (D) 11.2 ml

55MOLE CONCEPT


Q.1 A partially dried clay mineral contains 8% water. The original sample contained 12 % waterand 45 % silica. The % of silica in the partially dried sample is nearly :(A) 50 % (B) 49 % (C) 55 % (D) 47 %

Q.2 When one gram mole of KMnO4 reacts with HCl, the volume of chlorine liberated at NTP

will be :(A) 11.2 litres (B) 22.4 litres (C) 44.8 litres (D) 56.0 litres

Q.3 8 g of sulphur is burnt to form SO2 which is oxidised by Cl

2 water. The solution is treated with

BaCl2 solution. The amount of BaSO

4 precipitated is :

(A) 1 mole (B) 0.5 mole (C) 0.24 mole (D) 0.25 mole

Q.4 1 gram of a carbonate of a metal was dissolved in 25 ml of 1N HCl. The resulting liquidrequired 5 ml of N NaOH for neutralization. The eq. wt. of metal carbonate is :(A) 100 (B) 30 (C) 40 (D) 50

Q.5 Sulphuryl chloride SO2Cl

2 reacts with water to give a mixture of H

2SO

4 and HCl. How many

moles of NaOH would be needed to neutralize the solution formed by adding 1 mole ofSO

2Cl

2 to excess of water .

(A) 1 (B) 3 (C) 2 (D) 4

Q.6 Hydrogen peroxide in aqueous solution decomposes on warming to give oxygen according tothe equation 2H

2O

2(aq.) → 2H

2O(l) + O

2(g) under conditions where one mole of gas

occupies 24 dm3, 100 cm3 of XM solution of H2O

2 produces 3dm3 of O

2. X is thus :

(A) 2.5 (B) 1 (C) 0.5 (D) 0.25

Q.7 In an experiment 50 ml of 0.1 M solution of a salt reacted with 25 ml of 0.1 M solution ofsodium sulphite. The half equation for the oxidation of sulphite ion is –

SO3

2– (aq.) + H2O(l) → SO

42– (aq.) + 2H+ (aq.) + 2e–

If the oxidation number of metal in the salt was 3, what would be the new oxidation numberof metal ?(A) 0 (B) 1 (C) 2 (D) 4

Q.8 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 Na

2CO

3. How many grams more of NaOH would it

require for conversion into Na2CO

3 if the mixture (one mole) is completely oxidized to CO

2 .

(A) 60 grams (B) 80 grams (C) 40 grams (D) 20 grams

Q.9 When BrO3

– ion reacts with Br– ion in acid solution Br2 is liberated the equivalent weight of

KBrO3 in this reaction is :

(A) M/8 (B) M/3 (C) M/5 (D) M/6[ where M is the molar mass ]

Q.10 A solution contains both Na2CO

3 and NaHCO

3 was treated with excess of CaCl

2 solution and

filtered. The precipitate weighed m1 grams. On adding NaOH in drops to the filtrate avoiding

excess, a further m2 grams was precipitated. If after adding excess CaCl

2, the solution (had not

been filtered) but was simply boiled and then filtered, what would be the total weight of theprecipitate ?(A) (m

1 + m

2) grams (B) (m

1 + m

2/2) grams

(C) (m1 + m

2) /2 grams (D) (m

2+m

1/2) grams

56 MOLE CONCEPT


Q.11 2 grams of a gas mixture of CO and CO2 on reaction with excess I

2O

5 yield 2.54 grams of I

2.

7What would be the weight % of CO in the original mixture ?(A) 70.1 (B) 75.3 (C) 68.4 (D) 80.7

Q.12 One gram of a mixture of Na2CO

3 and NaHCO

3 consumes y gram equivalents of HCl for

complete neutralisation. One gram of the mixture is strongly heated, then cooled and theresidue treated with HCl. How many gram equivalents of HCl would be required for completeneutralisation :(A) 2y gram equivalent (B) y gram equivalents(C) 3y/4 gram equivalents (D) 3y/2 gram equivalents

Q.13 In an organic compound of molar mass greater than 100 containing only C, H and N, thepercentage of C is 6 times the percentage of H while the sum of the percentages of C and H is1.5 times the percentage of N. What is the least molar mass :(A) 175 (B) 140 (C) 105 (D) 210

Q.14 One gram of a variable alloy of lead and tin yielded on treatment with conc. HNO3, filtration

and heating 0.42 grams of SnO2. If all the lead in one gram of alloy is converted into PbSO

4,

what will be the weight of PbSO4 obtained ?

(A) 0.98 (B) 1 g (C) 1.07 g (D) 0.95 g

Q.15 An iodide solution, ½ litre containing 0.664 grams of KI per litre, required 100 ml of a certainsolution of Ce4+ ion for complete reaction. What is the normality of the Ce4+ solution ?(A) 0.04 (B) 0.004 (C) 0.02 (D) none of these

Q.16 A solution contains Na2CO

3 and NaHCO

3. 10 ml of the solution required 2.5 ml of 0.1 M

H2SO

4 for neutralisation using phenolphthalein as indicator. Methyl orange is then added when

a further 2.5 ml of 0.2 M H2SO

4 was required. The amount of Na

2CO

3 and NaHCO

3 in 1 litre

of the solution is :(A) 5.3 g & 4.2 g (B) 3.3 g & 6.2 g (C) 4.2 g & 5.3 g (D) 6.2 g & 3.3 g

Q.17 0.7 g of a sample of Na2CO

3. x H

2O were dissolved in water and the volume was made to

100 ml . 20 ml of this solution required 19.8 ml of N/10 HCl for complete neutralization. Thevalue of

x is :

(A) 7 (B) 3 (C) 2 (D) 5

Q.18 34 g of hydrogen peroxide is present in 1120 ml of solution. This solution is called :(A) 10 vol solution (B) 20 vol solution (C) 30 vol solution (D) 32 vol solution

Q.19 Exactly 4.00 gm of a solution of H2SO

4 was diluted with water and excess BaCl

2 was added.

The washed and dried precipitate of BaSO4 weighed 4.08 gm. Find the percent H

2SO

4 in the

original acid solution.(A) 43.0 % (B) 4.3 % (C) 47 % (D) none

Q.20 What volume of 96 % H2SO

4 by weight solution (density 1.83 g/ml) is required to prepare

2.00 L of 3.00 M H2SO

4 solution ?

(A) 335 ml (B) 670 ml (C) 167.5 ml (D) none

57MOLE CONCEPT


Q.1 10.78 g of H3PO

4 in 550 ml solution is 0.40 N. Thus this acid :

(A) has been neutralised to HPO4

2– (B) has been neutralized to PO4

2–

(C) has been reduced to HPO3

2– (D) has been neutralised to H2PO

4–

Q.2 0.1 mol of MnO4

– (in acidic medium) can :(A) oxidise 0.5 mol of Fe2+ (B) oxidise 0.166 mol of FeC

2O

4

(C) oxidise 0.25 mol of C2O

42– (D) oxidise 0.6 mol of Cr

2O

72–

Q.3 Which of the following quantities are independent of temperature(A) Molarity (B) mole fraction (C) molality (D) normality

Q.4 1 mol BaF2 + 2mol H

2S

4 resulting mixture will be neutralised by :

(A) 1 mol of KOH (B) 2 mol of Ca(OH)2

(C) 4 mol KOH (D) 2 mol of KOH

Q.5 Which of the following represent redox reactions :(A) Cr

2O

72– + 2OH– 2CrO

42– + H

2O

(B) 2CrO4

2– + 2H+ Cr2O

72– + H

2O

(C) 2MnO4

– + 3Mn2+ + 4OH 5 MnO2 + 2H

2O

(D) 2Cu+ Cu + Cu2+

Q.6 When (NH4)

2 Cr

2O

7 is heated :

(A) there is oxidation of N (B) there is reduction of Cr(C) net reaction is disproportionations (D) net reaction is neutralisation

Q.7 Which of the following are disproportionation reaction ?

(A) 2RCHO → 3)OEt(Al RCOOCH2R (B) 4H

3PO

3 →

∆ 3H3 PO

4 + PH

3

(C) NH4NO

3 →

∆ N

2O + 2H

2O (D) PCl

5 →

∆ PCl3 + Cl

2

Q.8 For the reaction : H3PO

4 + Ca(OH)

2 CaHPO

4 + 2H

2O

1 mol 1 mol

Which are true statements :(A) equivalent weight of H

3PO

4 is 49

(B) resulting mixture is neutralised by 1 mol of KOH(C) CaHPO

4 is an acid salt

(D) 1 mol of H3PO

4 is completely neutralised by 1.5 mol of Ca(OH)

2.

Q.9 3H3PO

2 PH

3 + 2H

3PO

3 . In this reaction :

(A) H3PO

2 undergoes disproportionation (B) equivalent weight of H

3PO

2 is 22

(C) equivalent weight of H3PO

2 is 49.5 (D) NaH

2PO

2 is not acid salt.

Q.10 11.2 g of mixture of MCl (volatile) and NaCl gave 28.7 g of white ppt with excess of AgNO3

solution. 11.2 g of same mixture on heating gave a gas that on passing into AgNO3 solution

gave 14.35 g of white ppt. Hence:(A) ionic mass of M+ is 18(B) mixture has equal mole fraction of MCl and NaCl(C) MCl and NaCl are in 1 : 2 molar ratio(D) ionic mass of M+ is 10

58 MOLE CONCEPT


Q.11 H2C

2O

4 and NaHC

2O

4 behave as acids as well as reducing agents. which are correct statement?

(A) equivalent weight of H2C

2O

4 and NaHC

2O

4 are equal to their molecular weights when

behaving as reducing agents(B) 100 ml of 1 N solution of each is neutralised by equal volume of 1M Ca(OH)

2

(C) 100 ml of 1 N solution of each is neutralised by equal volume of 1N Ca(OH)2

(D) 100 ml of 1 M solution of each is oxidised by equal volumes of 1M KMnO4

Q.12 Which of the following are primary standard substances ?(A) Na

2CO

3.10H

2O (B) NaOH

(C) Na2B

4O

7.10H

2O (D) KMnO

4

Q.13 Which of the following statements are correct ?(A) the point at which an equivalent amount of the titrant is added is called the equivalence

point.(B) the point at which the reaction is observed to be complete is called the end point(C) at the end point of a reaction there is no change in the properties of the solution(D) at the equivalence point of a reaction the stoichiometric amount of the titrant is not

added

Q.14 100 mL of a 0.1 M SO42- solution is :

(A) 10 millimoles (B) 5 millimoles(C) 20 milliequivalents (D) 40 milliequivalent

Q.15 Which of following will be present in the solution formed when 50 mL of 0.1 M HCl ismixed with 50 mL of 0.1 M NaOH ?(A) 4.5 m mol of H+ (B) 0.05 m mol of OH-

(C) 0.05 M NaCl (D) 10-7 M of H+ ion

Q.16 Which of the following statements are correct ?(A) during the titration of a strong acid against a strong base, the pH at the at the equivalence

point will be neutral(B) during the titration of a weak acid against a strong base, the pH at the at the equivalence

point will be alkaline(C) during the titration of a weak acid against a strong base, the pH at the at the equivalence

point will be acidic(D) during the titration of a weak acid against a weak base, the pH at the at the equivalence

point will be neutral

Q.17 During the titration of a mixture of Na2CO

3 and NaHCO

3 against HCl,

(A) phenolphthalein is used to detect the first end point(B) phenolphthalein is used to detect the second end point(C) methyl orange is used to detect the second end point(D) methyl red is used to detect the first end point

Q.18 1 mol of H2SO

4 will exactly neutralize

(A) 2 mol of ammonia (B) 1 mol of Ba(OH)2

(C) 0.5 mol of Ba(OH)2

(D) 2 mol of KOH

Q.19 At the end point there is a sharp change of colour in the indicator. This happens because the(A) pH at the end point changes sharply(B) structure of the indicator changes(C) colour of indicator is adsorbed by water(D) dissociation constants of acids and bases differ by ten

59MOLE CONCEPT


Q.20 ‘20 volumes’ of H2O

2 is equal to :

(A) 20% H2O

2 by mass (B) 6% H

2O

2 by mass

(C) 1.764 N (D) 3.528 N

Q.21 A solution of Na2S

2O

3 is standardized iodometrically against 0.1262 g of KBrO

3. This

process requires 0.45 mL of Na2S

2O

3 solution. What is the strength of the Na

2S

2O

3 ?

(A) 0.2 M (B) 0.1 M (C) 0.05 N (D) 0.1 N

Q.22 Which of the following expressions is correct ( n = no. of moles of the gas, NA = Avogadro

constant, m = mass of molecule of the gas, N= no. of molecules of the gas)(A) n = mN

A(B) m = nN

A(C) N = nN

A(D) m = mn/N

A

Q.23 In which of the following pairs do 1g of each have an equal number of molecules?(A) N

2O and CO (B) N

2 and C

3O

2(C) N

2 and CO (D) N

2O and CO

2

Q.24 Among the following, which solutions contain equal numbers of millimoles ?(A) 100 mL of 0.05 M H

2SO

4(B) 200 mL of 0.0 M NaOH

(C) 100 mL of 0.10 M Na2C

2O

4(D) 200 mL of 0.025 MKOH

Q.25 1 mol of 3147 N− ions contains

(A) 4NA electrons (B) 7N

A protons (C) 7N

A neutrons (D) 14N

A protons

Q.26 11.2 L of gas at stp weighs 14.0 g. The gas could be :(A) N

2O (B) NO

2(C) N

2(D) CO

Q.27 The oxidation number of Cr = + 6 in :(A) FeCr

2O

4(B) KCrO

3Cl (C) CrO

5(D) [Cr(OH)

4]–

Q.28 The oxidation number of carbon is zero in :(A) HCHO (B) CH

2Cl

2(C) C

6H

12O

6(D) C

12H

22O

11

Q.29 Which of the following are not redox reactions ?(A) Mg + N

2 → Mg

3N

2

(B) K4[Fe(CN)

6] + H

2SO

4 + H

2O → K

2SO

4 + CO + FeSO

4 + (NH

4)

2SO

4

(C) I2 + 3Cl

2 → ICl

3

(D) CuSO4 + NH

3 → [Cu(NH

3)

4]SO

4

Q.30 Which of the following are redox reactions ?(A) NaIO

3 + NaHSO

3 → NaHSO

4 + Na

2SO

4 + I

2 + H

2O

(B) FeCl3 + K

4[Fe(CN)

6] → KCl + Fe

4[Fe(CN)

6]

3

(C) AgCl + Na2S

2O

3 → Na

3[Ag(S

2O

3)

2] + NaCl

(D) NaBiO3 + MnSO

4 + HNO

3 → HMnO

4 + Bi(NO

3)

3 + NaNO

3 + Na

2SO

4 + H

2O

Q.31 Which among the following are examples of autoredox reactions?(A) P

4 + OH– → H

2PO

4– + PH

3(B) S

2O

32– → SO

42– + S

(C) H2O

2 → H

2O + O

2(D) AgCl + NH

3 → [Ag(NH

3)

2]Cl

Q.32 The oxidation number of S= +6 in(A) peroxomonosulphuric acid (Caro’s acid)(B) peroxodisulphuric acid (Marshall’s acid)(C) pyrosulphuric acid (oleum)(D) sodium thio sulphate (hypo)

Q.33 Which of the following have been arranged in order of decreasing oxidation number of sulphur?(A) H

2S

2O

7 > Na

2S

4O

6 > Na

2S

2O

3 > S

8(B) SO2+ > SO

42– > SO

32– > HSO

4–

(C) H2SO

5 > S

2SO

3 > SCl

2 > H

2S (D) H

2SO

4 > SO

2 > H

2S > H

2S

2O

8

60 MOLE CONCEPT


Q.34 Calculate the amount of lime (CaO) produced by heating 100 g of 90% pure limestone.(A) 50.4 g (B) 0.98 mol (C) 0.90 mol (D) 56.0 g

Q.35 2 mol of CO2 is required to prepare

(A) 336 of NaHCO3

(B) 168 g of NaHCO3

(C) 463 g of Ca(HCO3)

2(D) 162 g of Ca(HCO

3)

2

Q.36 1.5 g of oxygen is produced by heating KClO3. How much KCl is produced in the reaction?

(A) 4.15 x 10–2 mol (B) 4.33 g (C) 1.78 x 10–2 mol (D) 1.33 g

Q.37 Which of the following gases are absorbed by an ammoniacal cuprous chloride solutions ?(A) NO (B) CO (C) O

3(D) C

2H

2

Q.38 50 milliliters of CO is mixed with 20 mL of oxygen and sparked. After the reaction, the mixtureis treated with an aqueous KOH solution. Choose the correct option.(A) The volume of the CO that reacts = 40 mL(B) The volume of the CO

2 formed = 40 mL.

(C) The volume of the CO that remains after treatment with KOH = 10 mL(D) The volume of the CO that remains after treatment with KOH = 20 mL

61MOLE CONCEPT


Q.1 If volume strength of H2O

2 solution is ‘X-V’ then its

Column I Column II

(a) Strength in g/L (i) 2.11X

(b) Volume strength X (ii) 6.5X

(c) Molarity (iii)6.5X17

(d) Normality (iv) 5.6 × N(A) (a)

-

(iii) , (b)

-

(i) , (c)

-

(iv) , (d)

-

(ii) (B) (a)

-

(iv) , (b)

-

(i) , (c)

-

(ii) , (d)

-

(i)

(C) (a) -

(iii) , (b)

-

(iv) , (c)

-

(i) , (d)

-

(ii) (D) (a)

-

(iii) , (b)

-

(ii) , (c)

-

(iv) , (d)

-

(i)

Q.2 Column I Column IIReactant n-factor

(a) H3PO

3(i) 11/3

(b) H3PO

4(ii) 2

(c) 3MnO4

– → 2Mn2+ + Mn+6 (iii) 3(d) FeC

2O

4 → Fe3+ + 2CO

2

(e) 2H2O

2 → O

2 + 2H

2O

(A) (a) -

(ii) , (b)

-

(iii) , (c)

-

(i) , (d)

-

(iii), (e)-(ii)

(B) (a) -

(i) , (b)

-

(ii) , (c)

-

(iii) , (d)

-

(ii), (e)-(i)

(C) (a) -

(ii) , (b)

-

(i) , (c)

-

(ii) , (d)

-

(iii), (e)-(ii)

(D) (a) -

(iii) , (b)

-

(ii) , (c)

-

(i) , (d)

-

(ii), (e)-(iii)

Q.3 Column I Column II(a) HClO

4(i) Oxidising agent

(b) H2S (ii) Reducing agent

(c) Na2S

2O

7(iii) Oxidising as well as reducing agent

(d) SO2

(e) HNO2

(A) (a) -

(ii) , (b)

-

(iii) , (c)

-

(i) , (d)

-

(iii), (e)-(ii)

(B) (a) -

(i) , (b)

-

(ii) , (c)

-

(iii) , (d)

-

(ii), (e)-(i)

(C) (a) -

(ii) , (b)

-

(i) , (c)

-

(ii) , (d)

-

(iii), (e)-(ii)

(D) (a) -

(i) , (b)

-

(ii) , (c)

-

(ii) , (d)

-

(iii), (e)-(iii)

Q.4 When mixture of 0.1 equivalent of each of the reactants mentioned under column I are reactedwith 1 M HCl solution. in presence of indicator phenolphthalein, the volume required in ml ofHCl solution for complete neutralization will be:

Column I Column II(a) Na

2CO

3 + NaHCO

3(i) 100 ml

(b) NaOH + NaHCO3

(ii) 150 ml(c) Na

2CO

3 + Na

2CO

3(iii) 50 ml

(d) Na2CO

3 + NaHCO

3 + NaOH

(A) (a) -

(i) , (b)

-

(iii) , (c)

-

(i) , (d)

-

(ii) (B) (a)

-

(i) , (b)

-

(ii) , (c)

-

(iii) , (d)

-

(ii)

(C) (a) -

(ii) , (b)

-

(i) , (c)

-

(ii) , (d)

-

(iii) (D) (a)

-

(iii) , (b)

-

(i) , (c)

-

(ii) , (d)

-

(ii)

62 MOLE CONCEPT


Q.5 Column I Column II

(a) MR on mixing two acidic solutions (i)

soluteM

10dx ××

(b) MR on mixing two basic solutions (ii) n × M × V ml

(c) MR on mixing acidic and basic solutions (iii)

21

2211

VV

VMVM

+

−

(d) milliequivalent (iv)2

11

V

VM

(e) Molarity (v)21

2211

VV

VMVM

+

+

(A) (a) -

(i) , (b)

-

(iii) , (c)

-

(i) , (d)

-

(ii), (e)-(iv)

(B) (a) -

(v) , (b)

-

(v) , (c)

-

(iii) , (d)

-

(ii), (e)-(i, iv)

(C) (a) -

(ii) , (b)

-

(i) , (c)

-

(ii) , (d)

-

(iii), (e)-(ii)

(D) (a) -

(i) , (b)

-

(ii) , (c)

-

(ii) , (d)

-

(iii), (e)-(iii)

63MOLE CONCEPT


Q.1 Find the number of mole of chloride ion needed to react with sufficient silver nitrate to make10.0 g of AgCl. What mass of CaCl

2 is required to provide this number of mole of Cl– ?

Q.2 How many kg of pure H2SO

4 could be obtained from 2.00 kg of pure iron pyrites (FeS

2)

according to the following reactions ?4FeS

2 + 11O

2 → 2Fe

2O

3 + 8SO

2 , 2SO

2 + O

2 → 2SO

3 , SO

3 + H

2O → H

2SO

4

Q.3 A solution contains 0.18 g/ml of a substance, X, whose molecular weight is approximately68000. It is found that 0.27 ml of oxygen at 760 mm and 30°C will combine with the amountof X contained in 1.0 ml of the solution. How many molecules of oxygen will combine withone molecule of X ?

Q.4 5g sample of brass was dissolved in one litre dil. H2SO

4. 20 ml of this solution were mixed

with Kl, liberating I2 and Cu+ and the I

2 required 20 ml of 0.0327 N hypo solution for

complete titration. Calculate the percentage of Cu in the alloy.

Q.5 A compound which contains one atom of X and two atoms of Y for each three atoms of Z ismade by mixing 5.00 g of X, 1.15 ×1023 atoms of Y and 0.03 mole of Z atoms. Given that only4.40 g of compound results. Calculate the atomic weight of Y if the atomic weights of X and Zare 60 and 80 amu respectively.

Q.6 Calculate the mass of oxalic acid which can be oxidized by 100ml of M MnO4– solution, 10ml

of which is capable of oxidizing 50ml of 1N I– to I2.

Q.7 The iodide content of a solution was determined by the titration with cerium (IV) sulphate in thepresence of HCl, in which I- is converted of ICl. A 250 ml sample of the solution required20 ml of 0.05 N Ce4+ solution. What is the iodide concentration in the original solution in g/litre.

Q.8 A solution is made by mixing 200 ml of 0.1M FeSO4, 200 ml of 0.1 M KMnO

4 and

600 ml of 1M HClO4. A reaction occurs in which Fe2+ is converted to Fe3+ & MnO

4– to Mn2+

in acid solution. Calculate the concentration of each ion.

Q.9 How many mole FeCl3 can be prepared by the reaction of 10.0g KMnO

4, 1.07 mol FeCl

2,

and 500 mL of 3.00 M HCl? MnCl2 is the reduction product.

Q.10 To 100ml of KMnO4 solution containing 0.632 gm of KMnO

4, 200 ml of SnCl

2 solution

containing 2.371 gm is added in presence of HCl. To the resulting solution excess of HgCl2 is

added all at once. How many gms of Hg2Cl

2 will be precipitated.

Q.11 How many gram KMnO4 should be taken to make up 250 mL of a solution of such

concentration that 1mL is equivalent to 5.00 mg iron in FeSO4?

Q.12 Exactly 40 ml of an acidified solution of 0.4 M iron (II) ion is titrated with KMnO4 solution.

After addition of 32 ml KMnO4, one additional drop turns the iron solution purple. Calculate

the concentration of permanganate solution.

Q.13 Potassium acid oxalate K2C

2O

4.3H

2C

2O

4.4H

2O can be oxidized by MnO

4- in acid medium.

Calculate the volume of 0.1M KMnO4 reacting in acid sol. with one gram of the acid oxalate.

Q.14 The reaction Cl2 + S

2O

32- → SO

42- + Cl- is to be carried out in basic medium. Starting with

0.15 mol of Cl2, 0.01 mol S

2O

32- and 0.3 mol of OH-, how many moles of OH- will be left in

solution after the reaction is complete. Assume no other reaction occurs.

64 MOLE CONCEPT


Q.15 0.5M KMnO4 solution completely reacts with 0.05M FeC

2O

4 solution under acidic conditions

where the products are Fe3+, CO2 and Mn2+. The volume of FeC

2O

4 used is 125 ml. What

volume of KMnO4 was used.

Q.1 K2Cr

2O

7 oxidizes HCl to Cl

2, which oxidizes K

2MnO

4. Calculate the weight of KMnO

4 formed

from one gram of potassium dichromate by reacting it with excess HCl and using the generatedchlorine for oxidizing K

2MnO

4 (Mn = 55; Cr = 52)

Q.2 A mixture of CaCl2 and NaCl weighing 2.385 g was dissolved in water and treated with a

solution of sodium oxalate which produces a precipitate of calcium oxalate. The precipitatewas filtered from the mixture and then dissolved in HCl to give oxalic acid which when titratedagainst 0.2M KMnO

4 consumed 19.64 mL of the latter. What was percentage by mass of

CaCl2 in the original sample?

Q.3 A certain volume of Ferric sulphate solution was reduced by excess of zinc and was thentitrated against 0.1N KMnO

4 solution. The titre value was 30 ml. The same volume of ferric

salt solution was reduced by another metal X and then titrated against 0.1 N KMnO4 and the

titre value was 45 ml. What are the oxidation states of metal X .

Q.4 1.44g pure FeC2O

4 was dissolved in dil. HCl and solution diluted to 100 mL. Calculate volume

of 0.01 M KMnO4 required to oxidize FeC

2O

4 solution completely.

Q.5 0.804 gm of a sample of iron ore was dissolved in acid. Iron was oxidized to +2 state and itrequired 117.2 ml of 0.112 N KMnO

4 solution for titration. Calculate the percentage of Fe and

FeO in the ore.

Q.6 KMnO4 oxidises X+n ion to XO3 –, itself changing to Mn+2 in acid solution. 2.68 × 10–3 mole of

X+n requires 1.61 × 10–3 mole of MnO4–. What is the value of n? Also calculate the atomic mass

of X, if the weight of 1 g equivalent of XCln is 56.

Q.7 A sample of Fe2(SO4)3 and FeC2O4 was dissolved in dil. H2SO4. The complete oxidation ofreaction mixture required 40 mL of N/16 KMnO4. After the oxidation, the reaction mixturewas reduced by Zn and dil. H2SO4. On again oxidation by same KMnO4, 60 mL were required.Calculate the ratio of Meq. of Fe2(SO4)3 and FeC2O4 in mixture.

Q.8 2.6 g sample of pyrolusite was boiled with 65 mL. of N oxalic acid and excess of dil. H2SO4.The liquid was then filtered and the residue washed. The filtrate and the washing were mixedand made upto 500 mL. 100 mL of this solution required 50 mL of N/10 KMnO4. Calculate %of MnO2 in sample.

Q.9 0.5 g sample of iron containing mineral mainly in the form of CuFeS2 was reduced suitably toconvert all the ferric ions into ferrous ions (Fe+3 → Fe+2) and was obtained as solution. In theabsence of any interfering radical, the solution required 42 mL of 0.01 M K2Cr2O7 for titration.Calculate % of CuFeS2 in sample.

Q.10 Mg can reduce NO3– to NH3 in basic solution:

NO3– + Mg(s) + H2O Mg(OH)2(s) + OH–(aq) + NH3(g)

A 25.0 mL sample of NO3– solution was treated with Mg. The NH3(g) was passed into mL of

0.15 N HCl. The excess HCl required 32.10 mL of 0.10 M NaOH for its neutralisation. Whatwas the molarity of NO3

– ions in the original sample?

65MOLE CONCEPT


NCERT TEXT BOOK EXERCISE

Q.1 Calculate the molecular mass of the following :(i) H

2O (ii) CO

2(iii) CH

4

Q.2 Calculate the mass per cent of different elements present in sodium sulphate (Na2O

4)

Q.3 Determine the empirical formula of an oxide of iron which has 69.9% iron and 30.1% dioxygenby mass.

Q.4 Calculate the amount of carbon dioxide that could be produced when(i) 1 mole of carbon is burnt in air(ii) 1 mole of carbon is burnt in 16 g of dioxygen(iii) 2 moles of carbon are burnt in 16 g dioxygen.

Q.5 Calculate the mass of sodium acetate (CH3COONa) required to make 500 mL of 0.375 molar

aqueous solution. Molar mass of sodium acetate is 82.0245 g mol–1.

Q.6 Calculate the concentration of nitric acid in moles per liter in a sample which has a density. 1.41g mL–1 and the mass per cent of nitric acid in it being 69%.

Q.7 How much copper can be obtained from 100 g of copper sulphate (CuSO4)?

Q.8 Determine the molecular formula of an oxide or iron in which the mass per cent of iron andoxygen are 69.9 and 30.1 respectively.

Q.9 Calculate the atomic mass (average) of chlorine using the following data;% natural abundance Molar mass

35Cl 75.77 34.968937Cl 24.23 36.9659

Q.10 In three moles of ethane (C2H

6), calculate the following:

(i) Number of moles of carbon atoms.(ii) Number of moles of hydrogen atoms(iii) Number of molecules of ethane.

Q.11 What is the concentration of sugar (C12

H22

O11

) in mol L–1 if its 20 g are dissolved in enoughwater to make a final volume up to 2L?

Q.12 If the density of methanol is 0.793 Kg L–1, what is its volume needed for making 2.5 L of its0.25 M solution?

Q.13 Pressure is determined as force per unit area of the surface. The SI unit of pressure, pascal isas shown below ?

1Pa = 1N m–1

If mass of air at sea level is 1034 g cm–2, calculate the pressure in pascal.

Q.14 What is the SI unit of mass? How is it defined ?

Q.15 A sample of drinking water was found to be severely contaminated with chloroform, CHCl3,

supposed to be carcinogenic in nature. The level of contamination was 15 ppm(by mass)(i) express this in percent by mass(ii) determine the molality of chloroform in the water.

66 MOLE CONCEPT


Q.16 Match the following prefixes with their multiples.Prefixes Multiples

(i) micro 106

(ii) deca 109

(iii) mega 10–6

(iv) giga 10–15

(v) femto 10

Q.17 The following data are obtained when dinitrogen and dioxygen react together to formdifferent compounds.

Mass of dinitrogen Mass of dioxygen(i) 14 g 16 g(ii) 14 g 32 g(iii) 28 g 32 g(iv) 28 g 80 g

(a) Which law of chemical combination is obeyed by the above experimental data? Giveits statements.

(b) Fill in the blanks in the following conversions:(i) 1 km = ...................... mm = .......................... pm(ii) 1 mg = .........................kg = .............................ng(iii) 1 mL = ........................ L = ............................. dm3

Q.18 In a reaction A + B2 → AB

2

Identify the limiting reagent, if any, in the following reaction mixtures.(i) 300 atoms of A + 200 molecules of B (ii) 2 mol A + 3 mol B(iii) 2.5 mol A + 6 mol B

Q.19 Dinitrogen and dihydrogen react with each other to produce ammonia according to thefollowing chemical equation : N

2(g) + H

2(g) → 2NH

3 (g)

(i) Calculate the mass of ammonia produced if 2.00 × 103 g dinitrogen reacts with1.00 ×103 g of dihydrogen.

(ii) Will any of the two reactants remain unreacted ?(iii) If yes, which one and what would be tis mass ?

Q.20 How are 0.50 mol Na2CO

3 and 0.50 M Na

2CO

3 different ?

Q.21 If ten volumes of dihydrogen gas reacts with five volumes of dioxygen gas, how manyvolumes of water vapour would be produced ?

Q.22 Which one of the following will have largest number of atoms ?(i) 1 g Au (s) (ii) 1 g Na (s) (iii) 1 g Li (s) (iv) 1 g of Cl

2 (s)

Q.23 Calculate the molarity of a solution ethanol in water in which the mole fraction of ethanol is0.040.

Q.24 What will be the mass of one 12C atom in g ?

Q.25 Use the data given in the following table to calculate the molar mass of naturally occurringorgan isotopes.Isotope Isotopic molar mass Abundance36Ar 35.96755 g mol–1 0.337%38Ar 37.96272 g mol–1 0.063%40Ar 39.9625 g mol–1 99.600 %

67MOLE CONCEPT


Q.26 Calculate the number of atoms in each of the following :(i) 52 moles of Ar (ii) 52 u of He (iii) 52 g of He.

Q.27 A welding fuel gas contains carbon and hydrogen only. Burning a small sample of it in oxygengive 3.38 g carbon dioxide, 0.690 g of water and no other products. A volume of 10.0 L(measured at STP) of this welding gas is found to weight 11.6 g. Calculate :(i) empirical formula. (ii) molar mass of the gas, and (iii) molecular formula.

Q.28 Calcium carbonate reacts with aqueous HCl to give CaCl2 and CO

2 according to the

reaction, CaCO3 is required to react completely with 25 mL of 0.75 M HCl ?

Q.29 Chlorine is prepared in the laboratory by treating manganese dioxide (MnO2) with aqueous

hydrochloric acid according to the reaction4 HCl (aq) + MnO

2(s) → 2H

2O (I) + MnCl

2(aq) + Cl

2(g)

How many grams of HCl react with 5.0 g of magnese dioxide?

[ IIT-JEE FLASH BACK ]

1980Q.1 0.5 g of fuming H

2SO

4 (oleum) is diluted with water. This solution is completely neutralised by

26.7 mL of 0.4 N NaOH. Find the percentage of free SO3 in the sample solution.

Q.2 Find out the percentage of oxalate in a given sample of an oxalate salt of which when 0.3 gwere dissolved in 100 mL of water required 90 mL of N/20 KMnO

4 solution for complete

oxidation.

Q.3 One litre of a sample of hard water contains 1 mg of CaCl2 and 1 mg of MgCl

2. Find the total

hardness in terms of parts of CaCO3 per 106 parts of water by mass.

Q.4 One litre of a mixture of carbon monoxide and carbon dioxide is passed through a tube containingred hot charcoal. The volume now becomes 1.6 litre. Volumes are measured under similarconditions. Find the composition of gaseous mixture.

Q.5 1 Mg is burnt in a closed vessel which contains 0.5 g of O2.

(i) Which reactant is left in excess ?(ii) Find the weight of the excess reactant.

Q.6 A mixture contains NaCl and an unknown chloride MCl.(i) 1 g of this dissolved in water. Excess of acidified AgNO

3 solution is added to it.

2.567 g of a white precipitate is formed.(ii) 1 g of the original mixture is heated to 300ºC. Some vapours come out which are

absorbed in acidified AgNO3 solution. 1.341g of a white precipitate is obtained.

Find the molecular mass of the unknown chloride.

1981Q.7 If 0.50 mole of BaCl

2 is mixed with 0.20 mole of Na

3PO

4, the maximum number of moles of

Ba3(PO

4)

2 that can be formed is

(A) 0.70 (B) 0.50 (C) 0.20 (D) 0.10

68 MOLE CONCEPT


Q.8 One mole of N2H

4 loses ten moles of electrons to form a new compound Y. Assuming that all

the nitrogen appears in the new compound, what is the oxidation state of nitrogen in Y ?[ There is no change in the oxidation state of hydrogen ]

(A) -1 (B) -3 (C) +3 (D) +5

Q.9 A 1.00 gm sample of H2O

2 solution containing X percent H

2O

2 by weight requires X ml of a

KMnO4 solution for complete oxidation under acidic conditions. Calculate the normality of the

KMnO4 solution.

Q.10 Balance the following equation :(i) Cu

2O + H+ + NO

3– → Cu2+ + NO + H

2O

(ii) K4[Fe(CN)

6 + H

2SO

4 + H

2O → K

2SO

4 + FeSO

4 + (NH

4)

2SO

4 + CO

(iii) C2H

5OH + I

2 + OH– → CHI

2 + HCO

3– + I– + H

2O

Q.11 50 mL of an aqueous solution of H2O

2 was treated with an excess of KI solution and dilute

H2SO

4. The liberated iodine required 20 mL of 0.1 N Na

2S

2O

3 solution for complete

interaction. Calculate the concentration of H2O

2 in g/L.

1982Q.12 The oxidation number of carbon in CH

2O is

(A) -2 (B) +2 (C) 0 (D) +4

Q.13 Hydroxylamine reduces iron (III) according to the equation :2NH

2OH + 4Fe3+ → N

2O(g)↑ + H

2O + 4Fe2+ + 4H+

Iron (II) thus produced is estimated by titration with a standard permanganate solution. Thereaction is :

MnO4

– + 5Fe2+ + 8H+ → Mn2+ + 5Fe3+ + 4H2O

A 10 ml sample of hydroxylamine solution was diluted to 1 litre. 50 ml of this diluted solutionwas boiled with an excess of iron (III) solution. The resulting solution required 12 ml of0.02 M KMnO

4 solution for complete oxidation of iron (II). Calculate the weight of

hydroxylamine in one litre of the original solution.

Q.14 Find the equivalent mass of H3PO

4 in the reaction,

Ca(OH)2 + H

3PO

4 → CaHPO

4 + 2H

2O

Q.15 4 g of mixture of NaCl and Na2CO

3 were dissolved in water and volume made upto 250 mL.

15 mL of this solution required 50 mL of N/10 HCl for complete neutralisation. Calculate thepercentage composition of the original mixture.

Q.16 25 g of a sample of ferrous sulphate was dissolved in water containing dilute H2SO

4 and the

volume made up to one litre. 25 mL of this solution required 20 mL of N/10 KMnO4 solution

for complete oxidation. Calculate the percentage of FeSO4.7H

2O in the sample.

Q.17 In the following reactions, identify the species oxidised, the species reduced, the oxidisingagent and the reducing agent :(A) 4HCl + MnO

2 → MnCl

2 + 2H

2O + Cl

2 (B) SnCl

2 + 2FeCl

3 → SnCl

4 + 2FeCl

2

(C) 2H+ + Mg → Mg2+ + H2

(D) H2SO

4 + 2H

2S → 3S + 3H

2O

1983Q.18 3 g of salt of molecular weight 30 is dissolved in 250 g of water. The molality of the solution is

________ .

69MOLE CONCEPT


Q.19 The density of a 3 M sodium thiosulphate solution (Na2S

2O

3) is 1.25 g per ml. Calculate :

(i) the percentage by weight of sodium thiosulphate,(ii) the mole fraction of sodium thiosulphate and(iii) the molalities of Na+ and S

2O

32– ions.

Q.20 4.08 g of a mixture of BaO and an unknown carbonate MCO3 was heated strongly. The residue

weighed 3.64 g. This was dissolved in 100 mL of 1 N HCl. The excess acid required 16 ml of2.5 N NaOH solution for complete neutralization. Identify the metal M.

Q.21 Complete and balance the following reactions :(i) Zn + NO

3– → Zn2+ + NH

4+

(ii) Cr2O

7–2 + C

2H

4O → C

2H

4O

2 + Cr3+

(iii) HNO3 + HCl → NO + Cl

2

(iv) Ce3+ + S2O

82– → SO

42– + Ce4+

(v) Cl2 + OH– → Cl– + ClO–

1984Q.22 2.68 × 10–3 moles of a solution containing an ion An+ acquire 1.61 × 10–3 moles of MnO

4– for

the oxidation of An+ to AO3– in acid medium. What is the value of n ?

1985Q.23 5 mL of 8 N HNO

3, 4.8 mL of 5 N HCl and a certain volume of 17 M H

2SO

4 are mixed

together and made upto 2 litre. 30 mL of this acid mixture exactly neutralizes 42.9 mL ofNa

2CO

3 solution containing 1 g of Na

2CO

3.10H

2O in 100 mL of water. Calculate the amount

of sulphate ions in g present in solution.

Q.24 20 mL of a solution containing 0.2 g of impure sample of H2O

2 reacts with 0.316 g of

KMnO4 (acidic). Calculate :

(a) Purity of H2O

2

(b) Volume of dry O2 evolved at 27ºC and 750 mm Pressure.

Q.25 The number of moles of solute per kg of a solvent is called as(A) molarity (B) normality (C) mole fraction (D) molality

1986Q.26 The reaction, 2C + O

2 → 2CO is carried out by taking 24 g of carbon and 96 g O

2, find out:

(a) Which reactant is left in excess ?(b) How much of it is left ?(c) How many mole of CO are formed ?(d) How many g of other reactant should be taken so that nothing is left at the end of reaction ?

Q.27 How many mL of a 0.05 M KMnO4 solution are required to oxidise 2.0 g of FeSO

4 in a

dilute solution (acidic).

Q.28 A molal solution is one that contains one mole of a solute in :(A) 1000 g of the solvent (B) one litre of solvent(C) one litre of the solution (D) 22.4 litres of the solution

Q.29 Complete and balance the following reactions :(i) Mn2++ PbO

2 → MnO

4– + H

2O (ii) S + OH– → S

2– + S

2O

32–

(iii) ClO3

– + I– + H2SO

4 → Cl– + HSO

4– (iv) Ag+ + AsH

3 → H

3AsO

3 + H+

Q.30 Arrange the following in increasing oxidation number of iodineI

2 , HI , HIO

4 , ICl

70 MOLE CONCEPT


Q.31 Give proper reasoning for the following :(i) H

2S acts only as reducing agent while SO

2 can act both as a reducing agent and oxidising

agent.(ii) An acidified potassium dichromate paper on being exposed to sulphur dioxide turns

green.(iii) Mercuric chloride and stannous chloride cannot exist as such if present together in an

aqueous solution.

1987Q.32 (i) What is the weight of sodium bromate and molarity of solution necessary to prepare

85.5 ml of 0.672 N solution when the half-cell reaction is :BrO

3– + 6H+ + 6e– → Br– + 3H

2O

(ii) What would be the weight as well as molarity if the half-cell reaction is :2BrO

3– + 12H+ + 10e– → Br

2 + 6H

2O

Q.33 What is the strength in g per litre of a solution of H2SO

4, 12 mL of which neutralized 15 mL of

N/10 NaOH solution ?

Q.34 Dichromate ion in acid solution oxidizes stannous ion as

3Sn+2 + 14H+ + Cr2O

7–2 → 3Sn+4 + Cr+3 + 7H

2O

(a) If SnCl2 is the source of Sn+2, how many g of SnCl

2 would be contained in 2 litre of

0.1 N solution ?(b) If K

2Cr

2O

7 is the source of Cr

2O

7–2, what is the normality of solution containing

4.9 g K2Cr

2O

7 ion in 0.1 litre of solution ?

Q.35 The brown ring complex compound is formulated as [Fe(H2O)

5(NO)+]SO

4. The oxidation

state of the iron is :(A) 1 (B) 2 (C) 3 (D) 4

1988Q.36 A sugar syrup of weight 214.2 g contains 34.2 g of sugar (C

12H

22O

11). Calculate (i) molal

concentration and (ii) mole fraction of sugar in the syrup.

Q.37 A sample of hydrazine sulphate (N2H

6SO

4) was dissolved in 100 ml of water. 10 ml of this

solution was reacted with excess of ferric chloride solution and warmed to complete the reaction.Ferrous ion formed was estimated and it required 20 ml of M/50 potassium permanganatesolution. Estimate the amount of hydrazine sulphate in one litre of the solution.Reaction 4Fe+++ + N

2H

4 → N

2 + 4Fe++ + 4H+

MnO4

– + 5Fe++ + 8H+ → Mn++ + 5Fe+++ + 4H2O

Q.38 The equivalent weight of MnSO4 is half its molecular weight when it is converted to –

(A) Mn2O

3(B) MnO

2(C) MnO

4– (D) MnO

42–

Q.39 0.50 g of a mixture of K2CO

3 and Li

2CO

3 required 30 mL of 0.25 N HCl solution for

neutralization. What is % composition of mixture ?

Q.40 0.804 g sample of iron ore was dissolved in acid. Iron was oxidised to +2 state and it required47.2 mL of 0.112 N KMnO

4 solution for titration. Calculate % of Fe and Fe

3O

4 in ore.

Q.41 In which mode of expression, the concentration of a solution remains independent oftemperature ?(A) molarity (B) Normality (C) Formality (D) Molality

71MOLE CONCEPT


1989Q.42 An equal volume of a reducing agent is titrated separately with 1M KMnO

4 in acid, neutral

and alkaline media. The volumes of KMnO4 required are 20 ml in acid, 33.4 ml in neutral and

100 ml in alkaline media. Find out the oxidation state of manganese in each reduction product.Give the balanced equations for all the three half reactions. Find out the volume of 1M K

2Cr

2O

7

consumed, if the same volume of the reducing agent is titrated in acid medium.

Q.43 n-Butane is produced by the monobromination of ethane followed by Wurtz reaction.Calculate the volume of ethane at NTP to produce 55 g n-butane if the bromination takes placewith 90% yield and the Wurtz reaction with 85% yield.

Q.44 5.5 g of a mixture of FeSO4.7H

2O and Fe

2(SO

4)

3.9H

2O required 5.4 mL of 0.1 N KMnO

4

solution for complete oxidation. Calculate mole of hydrated ferric sulphate in mixture.

Q.45 The largest no. of molecules is in :(A)28 g of CO(B) 46 g of C

2H

5OH (C) 36 g of H

2O (D) 54 g of N

2O

5

1990Q.46 A mixture of H

2C

2O

4 (oxalic acid) and NaHC

2O

4 weighing 2.02g was dissolved in water and

the solution made upto one litre. Ten milliliter of the solution required 3.0 ml of 0.1N sodiumhydroxide solution for complete neutralization. In another experiment, 10.0 ml of the samesolution, in hot dilute sulphuric acid medium, required 4.0 ml of 0.1N potassium permanganatesolution for complete neutralization. Calculate the amount of H

2C

2O

4 and NaHC

2O

4 in the

mixture.

Q.47 A solid mixture 5 g consists of lead nitrate and sodium nitrate was heated below 600°C untilweight of residue was constant. If the loss in weight is 28%, find the amount of lead nitrate andsodium nitrate in mixture.

Q.48 Calculate molality of 1 litre solution of 93% H2SO

4 (w/v). The density of solution is 1.84 g mL–1.

Q.49 A mixture of HCOOH and H2C

2O

4 is heated with conc. H

2SO

4. The gas produced is collected

and on treating with KOH solution volume of the gas decreases by 1/6th. Calculate molar ratioof two acids in original mixture.

Q.50 5.7 g of bleaching powder was suspended in 500 mL of water. 25 mL of this suspension ontreatment with KI and HCl liberated iodine which reacted with 24.35 mL of N/10 Na

2S

2O

3.

Calculate % of available Cl2 in bleaching powder.

Q.51 The oxidation number of phosphorus in Ba(H2PO

2)

2 is

(A) +3 (B) +2 (C) +1 (D) –1

Q.52 5.0 g of bleaching powder was suspended in water and volume made upto half a litre. 20 mL ofthis suspension when acidified with acetic acid and treated with excess of KI solution liberatediodine which required 20 mL of a decinormal hypo solution for titration. Calculate percentageof available chlorine in bleaching powder.

1991Q.53 A 1.0 g sample of Fe

2O

3 solid of 55.2 percent purity is dissolved in acid and reduced by

heating the solution with zinc dust. The resultant solution is cooled and made upto 100.0ml. Analiquot of 25.0 ml of this solution requires 17.0 ml of 0.0167M solution of an oxidant fortitration. Calculate the number of electrons taken up by the oxidant in the reaction of the abovetitration.

72 MOLE CONCEPT


Q.54 A solution of 0.2g of a compound containing Cu2+ and C2O

42- ions on titration with 0.02M

KMnO4 in presence of H

2SO

4 consumes 22.6ml of the oxidant. The resultant solution is

neutralized with Na2CO

3, acidified with dil. acetic acid and treated with excess KI. The liberated

iodine requires 11.3 ml of 0.05 M Na2S

2O

3 solution for complete reduction. Find out the mole

ratio of Cu2+ to C2O

42- in the compound. Write down the balanced redox reactions involved in

the above titrations.

Q.55 The volume strength of 1.5 N H2O

2 solution is :

(A) 4.8 (B) 8.4 (C) 3.0 (D) 8.0

Q.56 Calculate no. of oxalic acid molecules in 100 mL of 0.02 N oxalic acid.

Q.57 The oxidation states of the most electronegative element in the products of the reaction betweenBaO

2 and H

2SO

4 are :

(A) 0 and -1 (B) -1 and -2 (C) -2 and 0 (D) -2 and +1

Q.58 Read the following statement and explanation and answer as per the options given below :Statement (S) : In the titration of Na

2CO

3 with HCl using methyl orange indicator, the volume

required at the equivalence point is twice that of the acid required using phenolphthalein indicator.Explanation (E) : Two moles of HCl are required for the complete neutralisation of one mole ofNa

2CO

3.

(A) Both S and E are true, and E is the correct explanation of S.(B) Both S and E are true, and E is not the correct explanation of S.(C) S is true but E is false(D) S is false but E is true

1992Q.59 For the redox reaction :

MnO4

– + C2O

4–2 + H+ → Mn2+ + CO

2 + H

2O

the correct coefficients of the reactants for the balanced reaction are –MnO

4– C

2O

42– H+

(A) 2 5 16(B) 16 5 2(C) 5 16 2(D) 2 16 5

Q.60 One gram of commercial AgNO3 is dissolved in 50 ml of water. It is treated with 50 ml of a KI

solution. The silver iodide thus precipitated is filtered off. Excess of KI in the filtrate is titratedwith (M/10) KIO

3 solution in presence of 6M HCl till all I– ions are converted into ICl. It

requires 50 ml of (M/10) KIO3 solution. Twenty milliliters of the same stock solution of KI

requires 30 ml of (M/10)KIO3 under similar conditions. Calculate the percentage of AgNO

3 in

the sample. (Reaction : KIO3 + 2KI + 6HCl → 3ICl + 3KCl + 3H

2O)

Q.61 A 2.0 g sample of a mixture of Na2CO

3, NaHCO

3 and Na

2SO

4 is gently heated till the

evolution of CO2 ceases. The volume of CO

2 at 750 mm of Hg and 298 K is measured to be

123.9 mL. A 1.5 g of the same sample requires 150 mL of M/10 HCl for completeneutralization. Calculate composition of mixture.

Q.62 A 0.56 g sample of limestone is dissolved in acid and the calcium is precipitated as calciumoxalate. The precipitate is filtered, washed with water and dissolved in dil. H

2SO

4. The solution

required 40 mL of 0.25 N KMnO4 solution for titration. Calculate % of CaO in limestone

sample.

73MOLE CONCEPT


Q.63 Complete & balance the reaction :K

2Cr

2O

7 + HCl → KCl + ........ + ........ + H

2O

Q.64 The mass of 1 × 1022 molecules of CuSO4.5H

2O is ................... .

Q.65 Give proper reasoning for the following : [CuCl4]2– is formed but [CuI

4]2– is not ?

1993Q.66 Upon mixing 45.0 mL of 0.25 M lead nitrate solution with 25 mL of 0.10 M chromic sulphate,

precipitation of lead sulphate takes place. How many mole of lead sulphate are formed ?Also calculate the molar concentrations of the species left behind in final solution. Assume thatlead sulphate is completely insoluble.

Q.67 In an ore, the only oxidizable material is Sn+2. This ore is titrated with a dichromate solutioncontaining 2.5 g of K

2Cr

2O

7 in 0.5 litre. A 0.40 g sample of the ore required 10.0 cm3 of titrant

to reach equivalent point. Calculate the percentage of tin in ore.

1994Q.68 8.0575 ×10–2 kg of Glauber’s salt is dissolved in water to obtain 1 dm3 of a solution of density

1077.2 kg m–3. Calculate the molarity, molality and mole fraction of Na2SO

4 in solution.

Q.69 The composition of a sample of wurtzite is Fe0.93

O1.00

. What percentage of the iron is presentin the form of Fe(III).

Q.70 0.5 g sample containing MnO2 is treated with HCl, liberating Cl

2. The Cl

2 is passed into a

solution of KI and 30.0 cm3 of 0.1 N Na2S

2O

3 are required to titrate the liberated iodine.

Calculate the percentage of MnO2 in sample. [ Atomic weight of Mn = 55 ]

Q.71 Complete & balance the reaction :(i) Sn + 2KOH + 4H

2O → ............. + ......................

(ii) MnO4

2– + H+ → MnO2 + MnO

4– + H

2O

Q.72 The compound YBa2Cu

3O

7 which show superconductivity, has copper in oxidation state

...................... Assume that the rare earth element yttrium is in its usual +3 oxidation state.

1995Q.73 A 5.0 cm3 solution of H

2O

2 liberates 0.508g iodine from an acidified KI solution. Calculate the

strength of H2O

2 solution in terms of volume strength at STP.

Q.74 A mixture of C2H

4 and C

2H

6 occupies 40L at 1 atm and 400 K. The mixture reacts completely

with 130 g of O2 to produce CO

2 and H

2O. Assuming ideal behaviour, Calculate the mole

fraction of C2H

4 and C

2H

6.

Q.75 A mixture of 20 mL of CO, CH4 and N

2 was burnt in excess of O

2 resulting in reduction of

13 mL of volume. The residual gas was then treated with KOH solution to show a contractionof 14 mL in volume. Calculate volume of CO, CH

4 and N

2 in mixture. All measurements are

made at constant pressure and temperature.

Q.76 0.5 g mixture of K2Cr

2O

7 and KMnO

4 was treated with excess of KI in acidic medium. Iodine

liberated required 100 cm3 of 0.15 N sodium thiosulphate solution for titration. Find the percentamount of each in the mixture.

74 MOLE CONCEPT


1996Q.77 A 3.00g sample containing Fe

3O

4, Fe

2O

3 and an inert impure substance, is treated with excess

of KI solution in presence of dilute H2SO

4. The entire iron is converted into Fe2+ along with

the liberation of iodine. The resulting solution is diluted to 100 ml. A 20 ml of the dilutedsolution require 11.0 ml of 0.5M Na

2S

2O

3 solution to reduce the iodine present. A 50 ml of

the diluted solution after complete extraction of the iodine requires 12.80 ml of 0.25 MKMnO

4 solution in dilute H

2SO

4 medium for the oxidation of Fe+2. Calculate the percentages

of Fe2O

3 and Fe

3O

4 in the original sample

Q.78 1.6 g of pyrolusite ore was treated with 50 cm3 of 1.0 N oxalic acid and some sulphuric acid.The oxalic acid left undecomposed was raised to 250 cm3 in a flask. 25 cm3 of this solutionwhen titrated with 0.1 N KMnO

4 required 32 cm3 of the solution. Find out the percentage of

pure MnO2 in the sample and also the percentage of available oxygen.

1997Q.79 One litre of a mixture of O

2 and O

3 at NTP was allowed to react with an excess of acidified

solution of KI. The iodine liberated required 40 ml of M/10 sodium thiosulphate solution fortitration. What is the percent of ozone in the mixture? Ultraviolet radiation of wavelength 300nm can decompose ozone. Assuming that one photon can decompose one ozone molecule,how many photons would have been required for the complete decomposition of ozone in theoriginal mixture?

Q.80 A sample of hard water contains 96 ppm. of SO4

2– and 183 ppm of HCO3

–, with Ca2+ as theonly cation. How many moles of CaO will be required to remove HCO

3– from 1000 kg of this

water ? If 1000 kg of this water is treated with the amount of CaO calculated above, whatwill be the concentration (in ppm) of residual Ca2+ ions (Assume CaCO

3 to be completely insoluble

in water) ? If the Ca2+ ions in one litre of the treated water are completely exchanged withhydrogen ions, what will be its pH (One ppm means one part of the substance in one millionpart of water, weight/weights) ?

Q.81 The number of moles of KMnO4 that will be needed to react completely with one mole of

ferrous oxalate in acidic medium.(A) 3/5 (B) 2/5 (C) 4/5 (D) 1

Q.82 The number of moles of KMnO4 that will be needed to react with one mole of sulphite ion in

acidic solution is–(A) 2/5 (B) 3/5 (C) 4/5 (D) 1

Q.83 1.20 g sample of Na2CO

3 and K

2CO

3 was dissolved in water to form 100 mL of a solution.

20 mL of this solution required 40 mL of 0.1 N HCl for complete neutralization. Calculatethe weight of Na

2CO

3 in mixture. If another 20 mL of this solution is treated with excess of

BaCl2, what will be the weight of precipitate ?

Q.84 To a 25 mL H2O

2 solution, excess of acidified solution of KI was added. The iodine liberated

required 20 mL of 0.3 N sodium thiosulphate solution. Calculate the volume strength of H2O

2

solution.

Q.85 Complete and balance the following equations :

(i) H2S + H

2SO

4 (conc.) → ...................... + .................. + .............

(ii) NaOH + I2 → ............... +....................... + H

2O

(iii) NH3 + NaOCl → ............... + NaCl + H

2O

75MOLE CONCEPT


1998Q.86 An aqueous solution containing 0.10g KIO

3 (formula wt. = 214.0) was treated with an excess

of KI solution. The solution was acidified with HCl. The liberated I2 consumed 45.0 ml of

thiosulphate solution to decolourise the blue starch - iodine complex. Calculate the molarity ofthe sodium thiosulphate solution.

Q.87 A sample of Mg was burnt in air to give a mixture of MgO and Mg3N

2. The ash was dissolved

in 60 Meq. of HCl and the resulting solution was back titrated with NaOH. 12 Meq. of NaOHwere required to reach the end point. An excess of NaOH was then added and the solutiondistilled. The ammonia released was then trapped in 10 Meq. of second acid solution. Backtitration of this solution required 6 Meq. of the base. Calculate the percentage of Mg burnt tothe nitride.

Q.88 For the reaction, N2O

5 (g) 2NO

2(g) + 0.5 O

2 (g), calculate the mole fraction of N

2O

5(g)

decomposed at a constant volume and temperature, if the initial pressure is 600 mm Hg and thepressure at any time 960 mm Hg. Assume ideal gas behaviour.

Q.89 Complete and balance the following equations :

(i) H2SO

2 + HI → ..................... + ...................... + ...............

(ii) CaOCl2 + NaI + HCl → ........... + CaCl

2 + H

2O + NaCl

(iii) Ag2S + 2CuCl

2 + 2Hg → ........... + .................. + S + 2 Ag

1999Q.90 The normality of 0.3 M phosphorus acid (H

3PO

3) is –

(A) 0.1 (B) 0.9 (C) 0.3 (D) 0.6

Q.91 A plant virus is found to consist of uniform cylindrical particles of 150 Å in diameter and 5000Å long. The specific volume of the virus is 0.75 cm3/g. If the virus is considered to be a singleparticle, find its molecular weight.

Q.92 How many ml of 0.5 M H2SO

4 are needed to dissolve 0.5 g of copper (II) carbonate.

Q.93 The oxidation number of S in S8, S

2F

2 and H

2S is ________.

Q.94 A mixture in which the mole ratio of H2 and O

2 is 2 : 1 is used to prepare water by the reaction,

2H2(g) + O

2(g) → 2H

2O(g)

The total pressure in the container is 0.8 atm at 20ºC before the reaction. Determine the finalpressure at 120ºC after reaction assuming 80% yield of water.

Q.95 12 g of an impure sample of arsenious oxide was dissolved in water containing 7.5 g of sodiumbicarbonate and the resulting solution was diluted to 250 mL. 25 mL of this solution wascompletely oxidised by 22.4 mL of a solution of iodine. 25 mL of this iodine solution reactedwith same volume of a solution containing 24.8 g of sodium thiosulphate (Na

2S

2O

3.5H

2O) in

one litre. Calculate the percentage of arsenious oxide in the sample. (Atomic mass of As = 75)

2000Q.96 Amongst these identify species with an atom in + 6 oxidation state :

(A) MnO4– (B) Cr(CN)

63– (C) NiF

62– (D) CrO

2Cl

2

Q.97 The formula weight of an acid is 82. 100 cm3 of a solution of this acid containing 39.0 g of theacid per litre were completely neutralized by 95.0 cm3 of aqueous NaOH containing 40.0 g ofNaOH per litre. What is the basicity of the acid ?

76 MOLE CONCEPT


Q.98 The reaction, 3ClO– (aq) → ClO3

– (aq) + 2Cl–(aq) is an example of(A) oxidation reaction (B) reduction reaction(C) disproportion reaction (D) decomposition reaction

Q.99 One mole of calcium phosphide on reaction with excess water gives :(A) 1 mole of phosphine (B) 2 moles of phosphine(C) 2 moles of phosphoric acid (D) 1 mole of phosphorus pentoxide

2001Q.100 Hydrogen peroxide solution (20 mL) reacts quantitatively with a solution of KMnO

4 (20 mL)

acidified with dilute H2SO

4. The same volume of the KMnO

4 solution is just decolorized by

10mL of MnSO4 in neutral medium simultaneously forming a dark brown precipitate of

hydrated MnO2. The brown precipitate is dissolved in 10mL of 0.2M sodium oxalate under

boiling condition in the presence of dilute H2SO

4. Write the balanced equations involved in the

reactions and calculate the molarity of H2O

2.

Q.101 At 100°C and 1 atm pressure, if the density of liquid water is 1.0 g cm-3 and that of watervapour is 0.0006 g cm–3, then the volume occupied by water molecules in 1 L of steam at thattemperature is :(A) 6 cm3 (B) 60 cm3 (C) 0.6 cm3 (D) 0.06 cm3

Q.102 A sample of MnSO4.H

2O is strongly heated in air. The residue (Mn

3O

4) left was dissolved in

100 mL of 0.1 N FeSO4 containing dil. H

2SO

4. This solution was completely reacted with 50

mL of KMnO4 solution. 25 mL of this KMnO

4 solution was completely reduced by 30 mL of

0.1 N FeSO4 solution. Calculate the amount of MnSO

4.4H

2O in sample.

Q.103 A sample weighing 2.198 g containing a mixture of AO and A2O

3 takes 0.015 mole K

2Cr

2O

7 to

oxidize the sample completely to form AO4– and Cr+3. If 0.0187 mole of AO

4– is formed, what

is atomic weight of A ?

Q.104 An aqueous solution of 6.3 gm oxalic acid dihydrate is made up to 250 ml. The volume of0.1 N NaOH required to completely neutralize 10 ml of this solution is :(A) 40 ml (B) 20 ml (C) 10 ml (D) 4 ml

Q.105 In the standardization of Na2S

2O

3 using K

2Cr

2O

7 by iodometry, the equivalent weight of

K2Cr

2O

7 is

(A) (molecular weight)/2 (B) (molecular weight)/6(C) (molecular weight)/3 (D) same as molecular weight

2002Q.106 How many moles of electron weight one Kg :

(A) 6.023 × 1023 (B) 108.9

1× 1031 (C)

108.9

023.6× 1054 (D)

023.6108.9

1

×× 108

2003Q.107 Calculate the molarity of water, if its density is 1000 kg/m3.

Q.108 1 g of charcoal adsorbs 100 mL of 0.5 M CH3COOH to form a monolayer and thereby the

molarity of CH3COOH reduces to 0.49. Calculate the surface area of the charcoal adsorbed

by each molecule of acetic acid. Surface area of charcoal = 3.01 × 102 m2/g.

77MOLE CONCEPT


Q.109 Which has maximum number of atoms(A) 24 g of C (B) 56 of Fe (C) 27 g of Al (D) 108 g of Ag

Q.110 Mixture X = 0.02 mol [Co(NH3)

5SO

4]Br & 0.02 mol of [Co(NH

3)

5Br]SO

4 was prepared in

2 litre solution.1 litre of mixture X + excess AgNO

3 → Y

1 litre of mixture X + excess BaCl2 → Z

No. of moles of Y & Z are :(A) 0.01, 0.01 (B) 0.02, 0.01 (C) 0.01, 0.02 (D) 0.02, 0.02

2004Q.111 The product of oxidation of I– in alkaline medium by MnO

4– is

(A) IO–1 (B) I2

(C) IO4

– (D) IO3

–

Q.112 The pair of the compounds in which both the metals are in the highest possible oxidationstate is(A) [Fe(CN)

6]3–, [Co(CN)

6]3– (B) CrO

2Cl

2, MnO

4–

(C) TiO3, MnO

2(D) [Co(CN)

6]3–, MnO

3

2005Q.113 O

3 does not oxidize which one of the following:

(A) KI (B) FeSO4

(C) KMnO4

(D) K2MnO

4

Q.114 Calculate the amount of calcium oxide required to react with 852 g of P4O

10.

78 MOLE CONCEPT


1. Daily Practice Problem Sheet

Q.1 (a) (+6) (b) (+2) (c) (+8) (d) (+2)(e) (0) (f) (+8/3) (g) (–2) (h) (+2)(i) (+7) (j) (+2) (k) (+1) (l) (+5/2)(m)

(0) (n)

(–1)

Q.2 (a) (+8) (b) (+4/3) (c) (+2) (d) (+5)(e) (+3) (f) (+2)

Q.3 (a) [+6, +4, +8/3, +2, +3, +4] (b) [–4, –3, –8/3, –2, –1, +3, +4](d) [+2, 0, 0, +6] (e) [–3, –1, –1/3, –3, +3](f) [0, +1, +1, +4, +5, +7]

Q.4 (a) [+5, –1, 0, +4] (b) [0, +5, –1]

Q.5 (a) (+4) (b) (+2) (c) (+6) (d) (–3)(e) (+3) (f)

(+5) (g) (–1) (h) (+3)

(i) (+6) (j) (+7) (k) (+2) (l) (+1)(m)

(+6) (n) (–1) (o) (+3) (p) (–1)

(q) (+1)


Q.1Rxn. No. (a) (b) (c) (d) (e) (f) (g) (h) (i) (j) (k)Oxidized : NaH, H

2S, Mg, none, SnCl

2, K, KI, NH

4+, none, none none.

Reduced : H2O, FeCl

3, N

2none, Br

2, AlCl

3, CusO

4, NO

2–, none, none, none

Q.2 (a) not (b) KIO3-oxidant, I– reductant

(c) CuSO4-oxidant, SO

2 reductant (d) Br

2-oxidant, C

2H

4 reductant

(e) H2O

2-oxidant, I– reductant (f) KOH-oxidant, Si reductant

(g) Cu++-oxidant, I– reductant


Q.1 1. 3C2H

5OH + Cr

2O

72– + 8H+ → 2Cr3+ + 3C

2H

4O + 7H

2O

2. 3Sn(OH)3

– + 2Bi(OH)3 + 3OH– → 3Sn(OH)

62– + 2Bi

3. IO3

– + N2H

4 + 2HCl → N

2 + ICl

2– + 3H

2O

4. 2Hg2Cl

2 + 4NH

3 → 2Hg + 2HgNH

2Cl + 2NH

4Cl

5. 4Zn + NO3

– + 10H+ → 4Zn2+ + NH4

+ + 3H2O

6. I2 + 10NO

3– +8H+ → 2IO

3– + 10NO

2 + 2H

2O

7. 2MnO4

– + 3SO2

2– + H2O → 2MnO

2 + 3SO

42– + 2OH–

8. H2O

2 + 2ClO

2 + 2OH– → 2ClO

2– + O

2 + 2H

2O

9. 3ClO– + 2CrO2

– + 2OH– → 3Cl– + 2CrO4

2– + H2O

79MOLE CONCEPT


10. 3Cl2 + 5KOH → KClO

3 + 5KCl + 3H

2O

11. 3H2O

2 + 2KMnO

4 → 2MnO

2 + 2KOH +3O

2 + 2H

2O

12. 5HNO2 + 2KMnO

4 + 3H

2SO

4 → 5HNO

3 + 2KMnO

4 + K

2SO

4 + 3H

2O

13. N2H

4 + 4AgNO

3 + 4KOH → N

2 + 4Ag + 4KNO

3 + 4H

2O

14. 3P + 5HNO3 → 3HPO

3 + 5NO + H

2O

15. K2Cr

2O

7 + 8HCl → 2KCl + 2CrCl

3 + 7H

2O + 3Cl

2

16. 2MnO4

– + 5C2O

42– + 16H+ → 10CO

2 + 2Mn2+ + 8H

2O

17. Cr2O

72– + 3C

2O

42– + 14H+ → 2Cr3+ + 6CO

2 + 7H

2O

18. 2KMnO4 + 5H

2S + 4H

2SO

4 → 2KHSO

4 + 2MnSO

4 + 5S + 8H

2O

19. 2Cu(NH3)

4Cl

2 + 7KCN + H

2O

→K2Cu(CN)

3 + 6NH

3 + KCNO + 2NH

4Cl + 2KCl

20. 4Ag + 8KCN + 2H2O + O

2 → 4KAg(CN)

2 + 4KOH

21. 6Fe3O

4 + 2MnO

4– + H

2O → 9Fe

2O

3 + 2MnO

2 + 2OH–

22. 3C2H

5OH + 2MnO

4– + OH– → 3C

2H

3O– + 2MnO

2 + 5H

2O

23. Cr2O

72– + 3SO

32– + 8H+ → 2Cr3+ + 3SO

42– + 4H

2O

24. 2ClO3

– + SO2 + H+ → 2ClO

2 + HSO

4–

25 2Mn2+ + 5S2O

82– + 8H

2O → 2MnO

4– + 10HSO

4– + 6H


Q.1 0.555 m, 0.0099 Q.2 64 gm

Q.3 9.027 M, 17.152 m, 0.236 Q.4 669.4 ml Q.5 1040 kg/m3

Q.6 5 M Q.7 (i) 3.06% (ii) 5.9M (iii) 8.6 m

Q.8 12.7 cm3 Q.9 5.84 % ethylene glycol, 94.16% solvent

Q.10 47.416 ml Q.11 56.1 cm3 Q.12 0.88 M

Q.13 1.5 × 10–3 %, 1.25 × 10–4 m Q.14 173.53 ml

Q.15 (i) 9.8 m (ii) 45.88%


Q.1 (i) 9.1% (ii) 5.357 N (iii) 2.678 M (iv) 91 g/L

Q.2 ‘20 V’

Q.3 (i) 17% (ii) 10 N (iii) 5 M (iv) 170 g/L

Q.4 34; 1120 ml Q.5 303.57 g/l

80 MOLE CONCEPT



1. 20% SO3

2. 10% SO3

3. 80%SO3

4. 120 g H2SO

4 and 80g SO

3

5. (a) 69 g H2SO

4, 40 g SO

3 (b) 118 g H

2SO

4 (c) 118 g H

2SO

4, 102 g water


1 (i) (a) 16.66 ppm (b) 500 ppm (ii) 0.972g

2. (i) 29.41 ppm (ii) 100 ppm (iii) 9 ppm (iv) 126.3 ppm

3. (i) 85.6 ppm (ii) 1.22 moles (iii) 36.75 ppm

4. 200 gm 5. 117.4 ppm of CaSO4


1. (i) SO2, (ii) 6.4 gm, (iii) 0.6 gm

2. (i) K2Cr

2O

7, (ii) 3.21 gm, (iii) 0.73 g HCl, (iv) 672 ml

3. (i) 0.64 gm, (ii) 1.634 gm, (iii) 0.9937 gm 4. 27.27 g, 2.73 g 5. 2.46 gm

6. 7.88 m 7. 1.476 : 1 8. 3.125% 9. A3O

4

10. 0.74 11. 4375 g 12. 1.52 Kg


1. 0.56 L 2. 5 g 3 1.27 g 4. 10 ml

5. 2l 6. 89.28% 7. 84% NaHCO3, 16% Na

2CO

3

8. Cu = 63.5, O =16 9. 49.8%

10. Pb(NO3)

2 = 3.324 gm ; NaNO

3 = 1.675 gm 11. 66.4% 12. 95.3%


1 4.6935 gm 2. x = 4 3. 1.5 4. 9.1055. 56 6. 0.2584 lit 7. m × a/2n 8. 39. 32 10. 32 11. 18.67 12. 3813. 6.2


1. (1) 2 (2) 2 (3) 1 (4) 1(5) 1 (6) 3 (7) 4 (8) 1(9) 2 (10) 1 (11) 10 (12) 2(13) 2 (14) 1 (15) 13

2. (1) 98 (2) 49 (3) 65.34 (4) 49

81MOLE CONCEPT


3. (1) 1 (2) 1 (3) 3 (4) 2(5) 5 (6) 3 (7) 6 (8) 1(9) 13 (10) 2

4. (1) 78 (2) 39 (3) 26 (4) 78

(5) 39


Q.1 1. 5 2. 1 3. 3 4. 65. 6 6. 1 7. 8 8. 29. 2 10. 2 11. 1 12. 313. 2 14. 6 15. 16 16. 217. 4 18. 6 19. 1 20. 221. 10 22. 12 23. 2/3 24. 225. 4 26. 8 27. 16 28. 629. 2 30. 16 31. 2 32. 133. 1 34. 0.15 35. 15 36. 1237. 8 38. 2 39. 16 40. 841. 24 42. 16 43. 8 44. 245. 2 46. 8 47. 2 48. 149. 2 50. 3

Q.2 1. 3 2. 10 3. 44/3 4. 285. 11 6. 27 7. 11 8. 109. 7 10. 4

Q.3 1. 5/3 2. 3/2 3. 2 4. 25. 1


1. KOH = 1.474 g, Ca(OH)2 = 2.726 g 2. 13.36 3. 8.71 %

4. acid is dibasic 5. 537.6 mL 6. 10 mL7. 400 mL 8. 1 : 2 9. 46.7 mL 10. 211. 107.9 mL 12. NaOH = 85.94 % Mg(OH)

2 = 14.06%

13. eq. wt. = 32.67, n = 3


1. NaOH = 1.92 g/l , Na2CO

3 = 3.392 g/l 2. Na

2CO

3 = 5g/L

3. NaOH = 3.2 g/L 4. Na2CO

3 = 0.053 g; NaHCO

3 = 0.021 g

5. Na2CO

3 = 0.053 g , KOH = 0.028 g 6. 34.4 ml, 55.8 ml, 21.3 m

7. Na2CO

3 = 1.27 g/L, NaOH = 3.02 g/L

8. NaOH = 0.1048 g/litre, Na2CO

3 = 0.1357 g/litre

9. 4.24 g litre–1, 4.48 g litre–1

82 MOLE CONCEPT



1. N = 0.5 , M - 0.167 2. N = 0.588 3. 66%4. 88.96% 5. V = 26.67 mL6. (i) N

H2SO4 = 0.0482, N

H2C2O4 = 0.0938

(ii) SH2SO4

= 2.362 g/lit , SH2C2O4

= 5.909 g/lit.7. 92.48% 8. 99% 9. 0.1716 M10. 2 and 5 11. Mn = 14.17% Cr = 20.83%12. (a) Cu = 90% & Zn = 10% (b) 9.558 mL13. 0.669% 14. 600 mL 15. 7.35 g litre–1

16. 5 17. 42.08% 18. 5.51 mL19. Fe

3O

420. 0.82


1. 10 ( i.e. Na2CO

3 .10H

2O) 2. 198 g/litre 3. 2.62 g and 3.38 g


1. 82.32% 2. 98.56% 3. 15.61%

1. A 2. C 3. B 4. D 5. B 6. D 7. A

8. B 9. A 10. C 11. C 12. B 13. C

1. D 2. D 3. D 4. D 5. D 6. A 7. C

8. A 9. C 10. B 11. C 12. B 13. B 14. A

15. C 16. A 17. C 18. A 19. A 20. A

1. AD 2. ABC 3. BC 4. CD 5. CD 6. AB 7. AB

8. ABCD 9. ACD 10. AB 11. ABD 12. AC 13. AB 14. AC

15. CD 16. ABC 17. AC 18. ABD 19. 20. AB 21. BD

22. BC 23. CD 24. AD 25. BC 26. CD 27. BC

28. ABCD 29. CD 30. AD 31. ABC 32. ABC 33. AC 34. AC

35. AD 36. CD 37. BD 38. ABC

83MOLE CONCEPT


1. C 2. A 3. D 4. D 5. B

1. 0.0697, 3.86 g 2. 3.26 kg 3. 4 4. 41.53%5. At. wt. of Y = 70 amu 6. 22.5 gm 7. 0.254 g/l

8. Fe3+ = 0.02M;MnO4- = 0.016 M ;

H+ = 0.568 M;Mn2+ = 0.004M; SO4--=0.02M;K+ = 0.02M, ClO

4- = 0.6M

9. 0.316 mol FeCl3

10. 1.176 gm 11. KMnO4 = 0.707g

12. 0.1M 13. V = 31.68 ml 14. 0.2 moles OH- 15. 7.5 ml

1. 3.22 gm 2. CaCl2 = 45.7% 3. +2 & +3

4. 600 mL MnO4- solution 5. % Fe = 61.43; %FeO = 38.57 6. n = 2, a = 97

7. 7 : 6 8. 66.92% 9. 92.48%

10. −3NO

N = 1.37, −3NO

M = 0.1716

16. ~15 × 10–4 g, 1.25 × 10–4 m

17. (a) law of multiple proportion (b) (i) (106 mm, 1015 pm) (ii) (106 kg, 109 ng) (iii) (10–3 L, 10–3 dm3)

18. (i) B is limiting (ii) A is limiting (iii) Stoichiometric mixture –No (iv) B is limiting (v) a is limiting

19. (i) 2571 g (ii) 428.5 g (iii) Hydrogen will remain unreacted 571.5 g

21. Ten volumes 24. 1.99265 × 10–23 g 25. 39.948 g mol–1

26. (i) 3.131 × 10–25 atoms (ii) 13 atoms (iii) 7.8286 × 10–24 atoms

27. Empirical formula CH, molar mass 22.0 g mol–1, molecular formula C2H

2.

28. 0.94 g CaCO3

29. 8.40 g HCl;

84 MOLE CONCEPT


1. 20.72 % 2. 66 % 3. 1.995 ppm 4. CO2 = 0.6 lit, CO = 0.4 lit

5. (i) Mg (ii) 0.25 gm 6. 53.5 7. D 8. C

9. 0.6 N 11. 0.68 g/L 12. C 13. 39.6g L–1

14. 49 15 . NaCl = 33.75 % Na2CO

3 = 66.25% 16. 88.96%

18. 0.4 19. (i) 37.92 (ii) 0.065 (iii) 7.72, 3.86 20. Ca

22. 2 23. 6.528 gm 24. (a) 85% (b) 12.479 mL

25. D 26. (a) O2 (b) 2 mole of O

2 (c) 2 mole of CO (d) 72 g carbon

27. 52.57 mL 28. A 30. HI < I2 < ICl < HIO

4

32. (i) 0.112 (ii) 0.1344 33. 6.125 gm/lit 34. (a) 18.97 gm (b) 1 N

35. B 36. (i) 0.56 (ii) 0.0099 37. Amount of N2H

6SO

4 = 6.5 gm/lit.

38. B 39. K2CO

3 = 96% , Li

2CO

3 = 4%

40. Fe = 36.82 % . Fe3O

4 = 50.87% 41. D 42. V = 16.67mL

43. 55.53 lit 44. 9.5 × 10–3 mol 45. C

46. H2C

2O

4 = 0.9 gm, NaHC

2O

4 = 1.12 gm 47. Pb(NO

3)

2 = 3.323 g, NaNO

3 = 1.677 g

48. 10.42 49. 4 : 1 50. 30.33% 51. C 52. 35.5%

53. 6 e– 54. Cu+2/C2O

4–2 = 1 : 2 55. B 56. 6.023 × 1020

57. B 58. B 59. A 60. 85% AgNO3

61. Na2CO

3 = 0.53 g, NaHCO

3, = 0.84g, Na

2SO

4 = 0.63g 62. 50% 64. 4.13 gms

66. 0.0075 mole of PbSO4, Pb2+ = 0.0536 M, NO

3– = 0.32 M, Cr3+ = 0.07

67. 15% 68. 0.25 M, 0.24 m, 4.3 ×10–3 69. 15.05 %

70. 26.1% 72. +7/3 73. 4.48 V 74. C2H

6 = 0.66, C

2H

4 = 0.34

75. 10 mL, 4 mL, 6 mL 76. 14.6% , 85.4%

77. Fe2O

3 = 49.33%, Fe

3O

4 = 34.8% 78. MnO

2 = 48.88% Percentage of available O

2 = 9%

79. 1.2 ×1021 photons; 6.57% O3 by weight 80. 3/2 moles of CaO, 40 ppm, 2.7

81. A 82. A 83. WNa2CO3

= 0.5962 gm, 0.394 gm

84. 1.344 86. 0.0623M 87. 27.27% 88. 0.4 90. D

91. 7.07 ×107 g /mol 92. 8.09 ml 93. 0, +1, –2

94. 0.787 atm 95. 9.24% 96. D 97. n = 2 98. C

99. B 100. 0.1 M 101. C 102. 1.338g

103. 100 104. A 105. B 106. D 107. 55.55 M

108. 5 × 10– 19 m2 109. A 110. A 111. D 112. B

113. C 114. 1.008 kg

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MOLE CONCEPT