MCQ CE

HKDSE Chemistry A Modern View Part X Chemical Equilibrium

Aristo Educational Press Ltd. 2010 201

Multiple Choice Questions Chemistry: Chapter 41 Dynamic equilibrium Section 41.1 1 Which of the following reactions are reversible? (1) HNO3(aq) + NaOH(aq) NaNO3(aq) + H2O(l) (2) NH4Cl(s) NH3(g) + HCl(g) (3) N2O4(g) 2NO2(g) A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

2 Which of the following reactions is/are irreversible? (1) CuSO4 5H2O(s) CuSO4(s) + 5H2O(l) (2) CaCO3(s) + 2HCl(aq) CaCl2(aq) + H2O(l) + CO2(g) (3) NH3(aq) + H2O(l) NH4+(aq) + OH(aq) A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

3 Which of the following reactions is NOT reversible? A. Rusting of iron B. Ionization of carbonic acid C. Formation of sulphur trioxide from sulphur dioxide and oxygen D. Formation of thiocyanatoiron(III) ion from iron(III) ion and thiocyanate ion

4 Which of the following is an irreversible reaction? A. Esterification between ethanoic acid and ethanol B. Ionization of sulphurous acid C. Industrial preparation of ammonia D. Rusting of iron



5 Which of the following are irreversible reactions? (1) Esterification between ethanoic acid and ethanol (2) Neutralization between a strong acid and a strong alkali (3) Rusting of iron A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

6 Which of the following reactions is/are reversible? (1) H2(g) + I2(g) 2HI(g) (2) Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g) (3) Fe(s) + CuSO4(aq) FeSO4(aq) + Cu(s) A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

7 Which of the following reactions are irreversible? (1) CH3CH2COOH(l) + CH3OH(l) CH3CH2COOCH3(l) + H2O(l) (2) 2Al(s) + 3H2SO4(aq) Al2(SO4)3(aq) + 3H2(g) (3) HNO3(aq) + KOH(aq) KNO3(aq) + H2O(l) A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

8 Consider the following reaction: 2SO2(g) + O2(g) 2SO3(g) Some 18O2 is introduced into the above reaction system, what will happen to the reaction mixture after an hour? A. 18O will only exist in O2(g). B. 18O will only exist in O2(g) and SO3(g).



C. 18O will only exist in O2(g) and SO2(g). D. 18O will exist in O2(g), SO2(g) and SO3(g).

9 Which of the following statements concerning the reaction below is INCORRECT? A + B C + D A. The forward reaction is A + B C + D. B. The backward reaction is C + D A + B. C. The reaction will not go to completion. D. The reaction will go to completion.

10 Which of the following processes is reversible? A. Dissolving carbonic acid in water B. Dissolving nitric acid in water C. Adding aluminium to sulphuric acid D. Adding zinc to copper(II) sulphate solution

11 Which of the following reactions is/are reversible? (1) Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g) (2) CH3COOH(l) + CH3CH2OH(l) CH3COOCH2CH3(l) + H2O(l)

(3) 2CrO42(aq) + 2H+(aq) Cr2O72(aq) + H2O(l) A. (1) only B. (2) only C. (1) and (2) only D. (2) and (3) only

12 Which of the following are reversible reactions? (1) HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l) (2) N2(g) + 3H2(g) 2NH3(g) (3) H2CO3(aq) + H2O(l) H3O+(aq) + HCO3(aq) A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)



13 Which of the following reactions is a reversible reaction? A. Dilute hydrochloric acid reacts with dilute sodium hydroxide solution. B. Thermal decomposition of calcium carbonate in an open container C. Testing for the presence of hydrogen gas in the pop sound test D. Nitrogen reacts with oxygen in a sealed flask.

14 Consider the following equilibrium reaction: CH3CH2OH(l) + CH3COOH(l) CH3COOCH2CH3(l) + H2O(l) Which of the following statements is correct?

A. CH3CH2OH(l) and CH3COOH(l) are used up at equilibrium. B. A fruity smell is detected even the system is not at equilibrium. C. Equilibrium can be attained by heating CH3CH2OH(l) and CH3COOH(l)

only. D. In the presence of catalyst, the reaction can go to completion.

Section 41.2 15 Which of the following statements concerning dynamic equilibrium is/are correct? (1) A reversible reaction stops when equilibrium is reached. (2) At equilibrium, the concentrations of reactants and products are constant. (3) At equilibrium, the concentrations of reactants and products are the same. A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

16 Which of the following statements concerning the chemical equilibrium below is/are correct? CaCO3(s) CaO(s) + CO2(g) (1) The above chemical equilibrium can only be established in a sealed container. (2) The reaction occurs spontaneously at room conditions. (3) Equilibrium can be reached from the backward direction of the reaction. A. (1) only B. (2) only C. (1) and (3) only



D. (2) and (3) only

17 Which of the following statements about chemical equilibrium is correct?

A. Both the forward and backward reactions stop when equilibrium is reached. B. The concentrations of reactants and products are still varying at equilibrium. C. The rate of forward reaction is equal to the rate of backward reaction at

equilibrium. D. The concentrations of reactants and products are equal at equilibrium.

18 When a small amount of N2O4(l) is introduced into a sealed container at a certain temperature, the following reaction occurs: N2O4(g) 2NO2(g) Which of the following statements concerning the change in colour of the reaction mixture with time is correct?

A. As time passes, the colour of the reaction mixture remains unchanged. B. As time passes, the colour of the reaction mixture changes gradually from

colourless to brown but at last changes back to colourless. C. As time passes, the colour of the reaction mixture changes gradually from

brown to colourless but at last changes back to brown. D. As time passes, the colour of the reaction mixture changes gradually from

colourless to brown but at last the brown colour persists.

19 Which of the following statements concerning the effect of catalysts on the reversible reactions is correct?

A. Catalysts increase either the rate of forward reaction or the rate of backward reaction of reversible reactions.

B. Catalysts shorten the time for the reversible reactions to reach equilibrium by increasing the rate of forward reaction and decreasing the rate of backward reaction.

C. Catalysts shorten the time for the reversible reactions to reach equilibrium by increasing both the rates of forward and backward reactions.

D. Catalysts increase the yield of products for reversible reactions.

20 Which of the following statements concerning reversible reactions is/are correct?



(1) Equilibrium of reversible reactions can only be established in a closed system. (2) As the reaction proceeds, the rate of forward reaction increases and the rate of

backward reaction decreases. (3) The concentration of reactant is the highest and the concentration of product is

the lowest at the beginning of the reaction. A. (1) only B. (2) only C. (1) and (2) only D. (1) and (3) only

21 When a small amount of N2O4(l) is introduced into a sealed container at a certain temperature, the following reaction occurs: N2O4(g) 2NO2(g) The following graph shows the changes in concentrations of N2O4(g) and NO2(g) with time.

Which of the following statements concerning the above graph are correct? (1) The reaction mixture reaches equilibrium at time T. (2) Curves X and Y represent the changes in concentrations of N2O4(g) and NO2(g)

with time respectively. (3) At time T, the rate of forward reaction is equal to the rate of backward reaction. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

22 Consider the following chemical equilibrium: 2H2S(g) 2H2(g) + S2(g) Which of the following statements concerning the above equilibrium are correct?

Time T

curve X curve Y

Con

cent

ratio

n



(1) When 2 molecules of H2(g) and 1 molecule of S2(g) combine, 2 molecules of H2S(g) decompose at the same time.

(2) The concentrations of H2S(g), H2(g) and S2(g) remain unchanged. (3) The pressure of the reaction mixture remains unchanged. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

23 Consider the following reversible reaction: N2O4(g) 2NO2 (g) Which of the following conditions are required to establish a chemical equilibrium for the above reaction at a certain temperature? (1) A closed system (2) Constant temperature (3) Constant pressure A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

24 Which of the following statements concerning a reversible reaction is INCORRECT?

A. Equilibrium can only be established in a closed system. B. Equilibrium can be reached from either the forward or the backward

direction of the reversible reaction. C. At equilibrium, there are observable changes of the reaction mixture as the

concentrations of reactants and products are still changing. D. At equilibrium, the rate of forward reaction is equal to the rate of backward

reaction.

25 Which of the following statements concerning a reaction at dynamic equilibrium are correct? (1) The forward and backward reactions still continue. (2) The concentrations of reactants and products are the same. (3) The rates of the forward and backward reactions are the same.



A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

26 When a small amount of N2O4 is introduced into a sealed container kept at 40C, the following reaction occurs: N2O4(g) 2NO2(g) Which of the following statements concerning the above reaction at equilibrium is/are correct? (1) The brown colour of the gaseous mixture remains unchanged. (2) The rate of the forward reaction is faster than the rate of the backward reaction. (3) The concentrations of NO2(g) and N2O4(g) are the same. A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

27 Which of the following statements concerning the chemical equilibrium below are correct? H2(g) + I2(g) 2HI(g) (1) The concentrations of H2(g), I2(g) and HI(g) are unchanged. (2) The colour of the reaction mixture remains constant. (3) When 2n mol of HI decomposes, n mol of H2 and n mol of I2 are combined at

the same time. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

28 When a small amount of N2O4(l) is introduced into a sealed container at a certain temperature, the following reaction takes place: N2O4(g) 2NO2(g) Which of the following graphs correctly shows the changes in concentrations of N2O4 and NO2 with time until the reaction reaches equilibrium?



A.

B.

C.

D.

29 Which of the following are the characteristics of dynamic equilibrium? (1) The reaction system for establishing equilibrium must be an open system. (2) At equilibrium, the rate of forward reaction is equal to the rate of backward

reaction. (3) At equilibrium, there are no observable changes in the reaction mixture. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

30 Equal numbers of moles of I2(g) and H2(g) are introduced in a sealed container at a certain temperature. The following reaction occurs: I2(g) + H2(g) 2HI(g) The reaction mixture is allowed to reach chemical equilibrium. Which of the following statements concerning the above chemical equilibrium is/are INCORRECT?

A. The rate of combination between I2(g) molecules and H2(g) molecules is equal to the rate of decomposition of HI(g) molecules.

B. The colour intensity of the reaction mixture remains constant. C. The concentrations of I2(g) and H2(g) are always the same. D. When 1 mol of HI(g) decomposes, 1 mol of I2(g) and 1mol of H2(g)

N2O4

NO2

Time

Con

cent

ratio

n N2O

NO2

Time

Con

cent

ratio

n

Con

cent

ratio

n

Time

NO2

N2O4

Con

cent

ratio

n

Time

NO2

N2O4



combine at the same time.

31 Which of the following statements concerning chemical equilibrium is INCORRECT?

A. There are no observable changes of the reaction mixture at chemical equilibrium.

B. Both forward and backward reactions are taking place at chemical equilibrium.

C. No reaction is taking place at chemical equilibrium. D. The concentrations of both products and reactants remain unchanged at

chemical equilibrium.

32 Which of the following conditions is required for a reaction to reach dynamic equilibrium? A. The initial concentrations of reactants must be 1.0 M. B. The reaction must be carried out at room pressure. C. The reaction must be carried out at room temperature. D. The reaction must be carried out in a closed system.

33 Which of the following statements concerning the chemical equilibrium below are correct? 2SO3(g) 2SO2(g) + O2(g) (1) At equilibrium, when 2 molecules of SO3(g) decompose, 2 molecules of SO2(g)

and 1 molecule of O2(g) combine at the same time. (2) The forward reaction is 2SO3(g) 2SO2(g) + O2(g). (3) At equilibrium, the concentrations of SO3(g), SO2(g) and O2(g) must be equal. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

34 Equal numbers of moles of ethanol and propanoic acid are heated under reflux in the presence of concentrated sulphuric acid. Which of the following statements concerning the above reaction are correct? (1) Ethanol, propanoic acid and ethyl propanoate are found in the reaction mixture.



(2) Concentrated sulphuric acid increases the rate of forward reaction only. (3) The reaction does not go to completion even if the reaction mixture is heated

under reflux for a long time. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

35 Which of the following diagrams best describes the rates of forward and backward reactions for the following reaction when M and N are heated in a container? M(s) + N(g) P(g) + Q(s)

A.

B.

C.

D.

36 The liquid water and water vapour in the bottle below are in equilibrium.

Which of the following statements are correct? (1) There is no change in the total amount of water vapour and liquid water. (2) The temperature of the system MUST be higher than 100C.

Con

cent

ratio

n

N(g)

P(g)

Time Time

N(g)

P(g) Con

cent

ratio

n

Time

Con

cent

ratio

n

P(g)

N(g) Con

cent

ratio

n

Time

N(g)

P(g)

water vapour

liquid water



(3) The rate of condensation is equal to the rate of vaporization. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

37 Which of the following is NOT a characteristic of chemical equilibrium?

A. The equilibrium can be reached by starting with either the reactants or the products.

B. It is a static situation where no chemical change is taking place. C. The chemical composition can be altered by changing the temperature. D. Addition of a catalyst can accelerate the rates of forward and backward

reactions.

38 Which of the following is a property of a reaction that has reached equilibrium? A. The amount of products is greater than the amount of reactants. B. The amount of products is equal to the amount of reactants. C. The rate of forward reaction is higher than the rate of backward reaction. D. The rate of forward reaction is equal to the rate of backward reaction.

39 The number of customers going into a shop per minute and the number of customers leaving the shop per minute are the same. The number of customers inside the shop remains constant. Which of the following best describes such a situation? A. Static equilibrium B. Dynamic equilibrium C. Loss of equilibrium state D. Chemical equilibrium

40 In dynamic equilibrium, which of the following properties of a reaction mixture remain constant? (1) Concentrations of all involved species (2) Colour intensity of the reaction mixture (3) Rates of reactions in both forward and backward directions A. (1) and (2) only



B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

41 Which of the following statements about dynamic equilibrium is INCORRECT?

A. At equilibrium, forward and backward reactions occur at the same rate. B. Equilibrium can be attained from either direction beginning with species on

only one side of the equation. C. Equilibrium can either be achieved in a closed system or an open system. D. At equilibrium, all macroscopic properties of an equilibrium mixture remain

constant.

42 The following reaction describes the dissociation of a chemical called ammonium carbamate. NH2COONH4(s) 2NH3(g) + CO2(g) This reaction takes place in a test tube without a stopper. However, no equilibrium state is observed. Which of the following statements best accounts for this observation?

A. The reaction is not carried out in a closed system and therefore cannot attain equilibrium.

B. The reaction actually attained equilibrium but it is not observable. C. Reversible reactions sometimes do not have an equilibrium state. D. None of the above.

43 Consider the following reversible chemical reaction: 2NO2(g) N2O4(g) Where NO2 is brown and N2O4 is colourless. When NO2 is used as the startingmaterial, the gas in a closed gas jar turns from brown to pale brown. Which of the following is the most probable observation when N

2O4 is used as the starting material? A. The gas turns from pale yellow to brown. B. The gas turns from colourless to brown. C. The gas turns from colourless to pale brown. D. The gas turns from brown to colourless.



44 Which of the following changes takes place in a closed system?

A. Reacting iron and dilute hydrochloric acid in a test tube B. Boiling water in a pressure cooker C. Crystallization of sodium chloride from a saturated sodium chloride

solution in a beaker D. Obtaining pure ethanol from a mixture of water and ethanol by distillation

45 Which of the following statements correctly describes an irreversible reaction?

A. Equilibrium can be attained when all the chemical species are kept in a closed container.

B. The rate of the forward reaction is always higher than that of the backward reaction.

C. The concentrations of reactants are increasing while the concentrations of products are decreasing.

D. The reaction stops until one of the reactants is used up.

46 Which of the following statements correctly describes the characteristics of dynamic equilibrium?

A. The concentrations of products are more than that of reactants at equilibrium.

B. The rates of the forward reaction and the backward reaction are equal to zero at equilibrium.

C. Equilibrium can be achieved from either the forward or the backward direction of a reversible reaction.

D. Equilibrium can only be established in an open system.

47 Which of the following graphs correctly describes the progress of a reversible reaction: A(g) B(g), starting with A(g), in a closed system at a constant temperature?



A. B.

C. D.

48 Apart from no changes in colour, which of the following observable properties of a system remain(s) unchanged at equilibrium? (1) pH (2) Opacity (3) Temperature A. (1) only B. (3) only C. (1) and (2) only D. (2) and (3) only

Each question below consists of two separate statements. Decide whether each of the two statements is true or false; if both are true, then decide whether or not the second statement is a correct explanation of the first statement. Then select one option from A to D according to the following table:

A. Both statements are true and the 2nd statement is a correct explanation of the 1st statement.

B. Both statements are true and the 2nd statement is NOT a correct explanation of the 1st statement.

C. The 1st statement is false but the 2nd statement is true. D. Both statements are false.

Con

cent

ratio

n

[B(g)]

[A(g)]

Time

[B(g)]

[A(g)]

Con

cent

ratio

n

Time

[B(g)]

Con

cent

ratio

n

[A(g)]

Time C

once

ntra

tion

Time

[A(g)]

[B(g)]



Section 41.1 49 Esterification is an irreversible reaction.

Dilute sulphuric acid can be used as a catalyst for this reaction.

Section 41.2 50 Chemical equilibrium is dynamic in nature.

Dynamic equilibrium can only be established in a closed system.

51 At equilibrium, the concentrations of reactants and products no longer change.

At equilibrium, the rates of forward and backward reactions are the same.

52 When calcium carbonate is exposed to air and heated strongly, the following reaction occurs: CaCO3(s) CaO(s) + CO2(g).

After some time, the reaction mixture reaches equilibrium.

53 If a reaction reaches dynamic equilibrium, both the forward and backward reactions are still continuing.

Dynamic equilibrium can only be established in a closed system.

54 When a reaction reaches equilibrium, there are no observable changes of the reaction mixture.

The rates of forward and backward reactions are the same at equilibrium.

55 The solution of ethanoic acid contains ethanoic acid molecules, ethanoate ions and hydrogen ions at equilibrium.

Ethanoic acid is a weak acid.

56



A catalyst can reduce the time for a reversible reaction to reach equilibrium by increasing the rate of forward reaction but decreasing the rate of backward reaction.

A catalyst usually increases the rate of a reaction.

Chemistry: Chapter 42 Equilibrium constant Section 42.1 57 Hydrogen sulphide decomposes to give hydrogen gas and sulphur gas: 2H2S(g) 2H2(g) +S2(g) Which of the following equilibrium constant expressions for the reaction is correct?

A. 2eqm2eqm2

2eqm2

c (g)][H (g)][SS(g)][H

K

B. eqm2eqm2

eqm2c (g)][S (g)][H

S(g)][HK

C. 2eqm2

eqm22eqm2

c S(g)][H(g)][S (g)][H

K

D. eqm2

eqm2eqm2c S(g)][H

(g)][S (g)][HK

58 What is the unit of the equilibrium constant for the following equilibrium system? 2NO2(g) N2O4(g) A. mol dm3 B. mol1 dm3 C. mol2 dm6 D. mol2 dm6

59 Which of the following combinations about the equilibrium below is correct? 4PF5(g) P4(g) + 10F2(g)

Equilibrium constant expression Unit



A. eqm5

eqm2eqm4

)]g(PF[)]g(F[)]g(P[

mol dm3

B. eqm2eqm4

eqm5

)]g(F[)]g(P[)]g(PF[

mol1 dm3

C. 4eqm5

10eqm2eqm4

)]g(PF[)]g(F[)]g(P[

mol7 dm21

D. 10eqm2eqm4

4eqm5

)]g(F[)]g(P[)]g(PF[

mol7 dm21

60 Which of the following CANNOT be the expression of equilibrium constant for an equilibrium mixture containing N2(g), H2(g) and NH3(g)?

A. 3eqm2eqm2

2eqm3

(g)][H(g)][N(g)][NH

B. 23

eqm221

eqm2

eqm3

(g)][H(g)][N

(g)][NH

C. eqm3

23

eqm221

eqm2

(g)][NH(g)][H(g)][N

D. eqm2eqm2

eqm3

(g)][H(g)][N(g)][NH

61 Which of the following equilibrium constant expressions for the reaction below is correct? CH4(g) + 2NO2(g) N2(g) + CO2(g) + 2H2O(g)

A. eqm2eqm2eqm2

eqm2eqm4

)]g(OH[)]g(CO[)]g(N[)]g(NO[)]g(CH[



B. 2eqm2eqm2eqm2

2eqm2eqm4

)]g(OH[)]g(CO[)]g(N[)]g(NO[)]g(CH[

C. 2eqm2eqm4

2eqm2eqm2eqm2

)]g(NO[)]g(CH[)]g(OH[)]g(CO[)]g(N[

D. eqm2eqm4

eqm2eqm2eqm2

)]g(NO[)]g(CH[)]g(OH[)]g(CO[)]g(N[

62 What is the unit of Kc for the following equilibrium system? 4NH3(g) + 5O2(g) 4NO(g) + 6H2O(g) A. no unit B. mol dm3 C. mol1 dm3 D. mol2 dm6

63 Which of the following mathematical relationships between K, K1 and K2 is correct? CO2(g) + H2(g) CO(g) + H2O(g) K Fe(s) + CO2(g) FeO(s) + CO(g) K1 Fe(s) + H2O(g) FeO(s) + H2(g) K2 A. K = K1 + K2 B. K = K1 K2

C. K = 2

1

KK

D. K = 1

2

KK

64 Consider the following reaction: H2(g) + I2(g) 2HI(g) Which of the following is the correct expression of the equilibrium constant, Kc, for the given reaction? A. Kc = [H2(g)]eqm[I2(g)]eqm B. Kc = 2[HI(g)]eqm



C. Kc = eqm2eqm2

eqm

(g)][I(g)][H2[HI(g)]

D. Kc = eqm2eqm2

eqm2

(g)][I(g)][H[HI(g)]

65 Consider the following reaction: N2(g) + 3H2(g) 2NH3(g) Which of the following is the correct expression of the equilibrium constant, Kc, for the given reaction? A. Kc = [N2(g)]eqm[H2(g)]3eqm B. Kc = [NH3(g)]2eqm

C. Kc = eqm2eqm

32

eqm2

3

(g)][N(g)][H(g)][NH

D. Kc = eqm2eqm2

eqm3

(g)][N(g)]3[H(g)]2[NH

66 What is the equilibrium expression for the Haber Process?

A. Kc = eqm2eqm2

eqm3

(g)][H(g)][N(g)][NH

B. Kc = ](g)[H(g)][N(g)]2[NH

eqm2eqm2

eqm3

C. Kc = eqm2eqm2

eqm3

(g)][H(g)]3[N(g)]2[NH

D. Kc = eqm

32eqm2

eqm2

3

(g)][H(g)][N(g)][NH

Section 42.2 67 What is the unit of the equilibrium constant for the following heterogeneous equilibrium? Fe3O4(s) + 4H2(g) 3Fe(s) + 4H2O(g) A. no unit B. mol2 dm6 C. mol4 dm12



D. mol1 dm3

68 Which of the following is the balanced chemical equation that gives the equilibrium constant expression shown below?

Kc = 2eqm2eqm4

4eqm

)]g(H[)]g(SiCl[)]g(HCl[

A. SiCl4(g) + 2H2(g) 4HCl(g) B. SiCl4(g) + 2H2(g) Si(s) + 4HCl(g) C. Si(s) + 4HCl(g) SiCl4(g) + 2H2(g) D. 4HCl(g) SiCl4(g) + 2H2(g)

69 What is the unit of the equilibrium constant for the following equilibrium system? 5CO(g) + I2O5(s) I2(g) + 5CO2(g) A. no unit B. mol dm3 C. mol1 dm3 D. mol2 dm6

70 For the following equilibrium system, what is the unit of Kc? 2NOCl(g) 2NO(g) + Cl2(g) A. no units B. mol dm3 C. mol1 dm3 D. mol2 dm6

71 What is the expression for the equilibrium constant, Kc, for the following reaction? Ag2CO3(s) Ag2O(s) + CO2(g) A. Kc = [CO2(g)]eqm

B. Kc = eqm2 (g)][CO

1

C. Kc = eqm2eqm2

eqm32

(g)][COO(s)][Ag(s)]CO[Ag



D. Kc = eqm32

eqm2eqm2

(s)]CO[Ag(g)][COO(s)][Ag

72 Consider the following reaction: H2(g) + I2(g) 2HI(g) Suppose the equilibrium constant of the given reaction at 298 K is Kc. Which is the correct expression of equilibrium constant, Kc, for the following reaction at 298 K? 2HI(g) H2(g) + I2(g) A. Kc = Kc

B. Kc = cK

1

C. Kc = Kc2

D. Kc = cK

73 Consider the following reaction: N2(g) + 3H2(g) 2NH3(g) Suppose the equilibrium constant of the given reaction at 298 K is Kc. Which is the correct equilibrium constant, Kc for the following reaction at 298 K?

21 N2(g) + 2

3 H2(g) NH3(g)

A. Kc = 2Kc

B. Kc = 21 Kc

C. Kc = Kc2

D. Kc = cK

74 Which is the correct expression of the equilibrium constant, Kc, for the following reaction? 2CrO42(aq) + 2H+(aq) Cr2O72(aq) + H2O(l)

A. Kc = eqm

2eqm

224

eqm2eqm2

72

(aq)][H(aq)][CrOO(l)][H(aq)]O[Cr



B. Kc = eqm2eqm

272

eqm2

eqm22

4

O(l)][H(aq)]O[Cr(aq)][H(aq)][CrO

C. Kc = eqm

2eqm

224

eqm2

72

(aq)][H(aq)][CrO(aq)]O[Cr

D. Kc = eqm

272

eqm2

eqm22

4

(aq)]O[Cr(aq)][H(aq)][CrO

75 Which is the correct expression of the equilibrium constant, Kc, of the following reaction? CaCO3(s) CaO(s) + CO2(g) A. Kc = [CO2(g)]eqm B. Kc = [CaCO3(s)]eqm C. Kc = [CaO(s)]eqm[CO2(g)]eqm

D. Kc = eqm3

eqm2eqm

(s)][CaCO(g)][CO[CaO(s)]

76 Consider the following reaction: N2(g) + O2(g) 2NO(g) Which of the following is the correct unit of the equilibrium constant, Kc, for the given reaction? A. dm3 mol1 B. mol dm3 C. mol2 dm6 D. no units

77 For a gaseous reaction, the expression for the equilibrium constant, Kc, is Kc =

eqm4

3eqm5

2

eqm4

(g)][NH(g)][O[NO(g)] ,

which of the following equations corresponds to this equilibrium expression? A. 5O2(g) + 4NH3(g) 4NO(g) + 6H2O(l) B. 4NO(g) + 6H2O(l) 5O2(g) + 4NH3(g)



C. 10O2(g) + 8NH3(g) 8NO(g) + 12H2O(l)

D. 2NO(g) + 3H2O(l) 25 O2(g) + 2NH3(g)

78 The value of Kc for the reaction H2(g) + CO2(g) H2O(g) + CO(g) is 1.45 at1100C. What is the value of K

c for the reaction H2O(g) + CO(g) H2(g) + CO2(g)at the same temperature?

A. 0.69 B. 0.83 C. 1.20 D. 1.45

79 Iron and steam react at a certain temperature according to the equation: 3Fe(s) + 4H2O(g) Fe3O4(s) + 4H2(g) The equilibrium constant, Kc, can be expressed as

A. Kc = eqm

42eqm

3eqm

42eqm43

O(g)][H[Fe(s)](g)][H(s)]O[Fe

B. Kc = eqm

42eqm43

eqm4

2eqm3

(g)][H(s)]O[FeO(g)][H[Fe(s)]

C. Kc = eqm

42

eqm4

2

O(g)][H(g)][H

D. Kc = eqm

42

eqm4

2

(g)][HO(g)][H

80 Which of the following reactions does not carry a unit in its equilibrium constant? A. 2H2(g) + O2(g) 2H2O(g) B. 2NO(g) N2(g) + O2(g) C. N2(g) + 3H2(g) 2NH3(g) D. COCl2(g) CO(g) + Cl2(g)

81



If the equilibrium constant for the reaction: CH3COOH + CN HCN + CH3COO is denoted as K, which of the following is the correct equilibrium constant, in terms of K, for the reaction: HCN + CH3COO CH3COOH + CN? A. K

B. K1

C. K2 D. It cannot be determined.

82 Which of the following reactions is NOT a homogeneous equilibrium? A. N2(g) + 3H2(g) 2NH3(g) B. 2NaHCO3(s) Na2CO3(s) + H2O(g) + CO2(g) C. 2HI(g) H2(g) + I2(g) D. CH4(g) + H2O(g) CO(g) + 3H2(g)

83 Which of the following is the expression for the equilibrium constant, Kc, for the reaction: CaCO3(s) CaO(s) + CO2(g)?

A. Kc = eqm3

eqm2eqm

(s)][CaCO(g)][CO[CaO(s)]

B. Kc = eqm2eqm

eqm3

(g)][CO[CaO(s)](s)][CaCO

C. Kc = [CO2(g)]

D. Kc = eqm2 (g)][CO

1

84 If the equilibrium constant for the reaction: A + B C is K, which of the following is the correct equilibrium constant for the reaction: 2C 2A + 2B? A. K2 B. K C. K1 D. K2

85 The expression for the equilibrium constant, Kc, of a gaseous reaction is as follows:



Kc = eqm

62eqm

4eqm

43eqm

52

O][H[NO]][NH][O

Which of the following equations corresponds to this expression? A. 4NH3 + 5O2 4NO + 6H2O B. 4NO + 6H2O 4NH3 + 5O2 C. 8NH3 + 10O2 8NO + 12H2O

D. 2NO + 3H2O 2NH3 + 25 O2

Section 42.3 86 Which of the following statements concerning the magnitude of equilibrium constant, Kc, is correct? A. It is affected by the change in pressure. B. If Kc is a positive value, the forward rate is faster than the backward rate. C. It indicates how far the equilibrium reaches. D. The larger the Kc value, the faster the reaction.

87 Which of the following statements concerning the equilibrium constant, Kc, is/are INCORRECT? (1) If Kc is larger than 1, it indicates that the amount of products is more than that of

reactants at equilibrium. (2) Kc gives the information about the rate of reaction. (3) Since the concentrations of liquids are constant in heterogeneous equilibria, they

do not appear in the expression for Kc. A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

88 The equilibrium constants of four different equilibrium systems are shown below.

Equilibrium system I II III IV Kc 3.2 105 4.7 1017 3.2 1017 4.7 105

Which of the equilibrium systems favours the reactants most?



A. I B. II C. III D. IV

89 Consider the following reaction: N2(g) + O2(g) 2NO(g) The equilibrium constant of the given reaction at 298 K is found to be 6.70 1013.

However, a scientist measured the value of (g)](g)][O[N

[NO(g)]

22

2

at some unknown

conditions and found a result of 2.30 107. Which of the following could be the possible reasons? (1) The reaction has not proceeded to equilibrium. (2) The reaction did not take place at a temperature of 298 K. (3) The reaction did not take place under a pressure of 1 atm. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

90 Consider the following reaction: 2SO2(g) + O2(g) 2SO3(g) At one equilibrium position, [SO2(g)]eqm, [O2(g)]eqm and [SO3(g)]eqm are 5.33 103

M, 3.70 10

3 M and 5.33 103 M respectively. Which of the following set of concentrations ([SO (g)] , [O (g)] and [SO (g)] respectively) constitutesanother equilibrium position at the same temperature?

2 eqm 2 eqm 3 eqm

A. 4.72 102 M, 1.013 105 M and 2.47 103 M B. 3.68 103 M, 5.284 105 M and 3.09 103 M C. 5.99 102 M, 1.221 105 M and 8.12 103 M D. 7.21 103 M, 4.592 105 M and 5.83 105 M

91 Assuming that the temperature is constant, which of the following reactions has the highest tendency to proceed towards completion?



A. N2(g) + O2(g) 2NO(g) Kc = 5.23 1027 B. 2HF(g) H2(g) + F2(g) Kc = 1.50 1022 C. 2NOCl(g) 2NO(g) + Cl2(g) Kc = 5.88 104 D. N2O4(g) 2NO2 (g) Kc = 49.7

92 A stronger base usually has a higher concentration of OH(aq) than a weaker base. The dissociation of a weak base, B(aq), in water can be represented by the following equation: B(aq) + H2O(l) BH+(aq) + OH(aq) Which of the following values of the equilibrium constant possibly represents the dissociation of a weak base? A. 1.00 105 B. 1.00 102 C. 1.00 102 D. 1.00 105

Section 42.4 93 Consider the following equilibrium: C(s) + CO2(g) 2CO(g) The equilibrium mixture was found to contain 0.42 mol dm3 of CO2(g) and 0.82 mol dm3 of CO(g) at a certain temperature. What was the equilibrium constant at that temperaure? A. 1.95 B. 1.60 mol dm3 C. 0.625 mol1 dm3 D. 0.512

94 At a certain temperature, the equilibrium constant, Kc, for the reaction C2H5CO2H(l) + C2H5OH(l) C2H5CO2C2H5(l) + H2O(l) is 4. When 1 mol dm3 of propanoic acid (C2H5CO2H) reacted with 1 mol dm3 of ethanol (C2H5OH) in the presence of concentrated sulphuric acid and the reaction mixture was allowed to reach equilibrium, what was the equilibrium concentration of propanoic acid in the mixture? A. 0.33 mol dm3



B. 0.67 mol dm3 C. 1 mol dm3 D. 2 mol dm3

95 At a certain temperature, the equilibrium constant, Kc, for the reaction I2(aq) + I(aq) I3(aq) is 68.75 mol1 dm3. In an experiment, 250 cm3 of 0.2 mol dm3 I2(aq) solution was mixed with 250 cm3 of 0.2 mol dm3 I(aq) solution. What is the equilibrium concentration of I3(aq) in the mixture? A. 0.0316 mol dm3 B. 0.0684 mol dm3 C. 0.0872 mol dm3 D. 0.1460 mol dm3

96 In Haber process, 0.60 mol dm3 of nitrogen is mixed with 1.80 mol dm3 of hydrogen in a sealed container at a certain temperature to give ammonia. N2(g) + 3H2(g) 2NH3(g) At equilibrium, 30% of the original nitrogen is consumed. What is Kc for this reaction? A. 0.154 mol2 dm6 B. 0.265 mol2 dm6 C. 0.680 mol2 dm6 D. 1.470 mol2 dm6

97 It is known that hydroxyapatite, Ca5(PO4)3OH, is present in our tooth enamel. It undergoes continuous reversible reactions with the minerals supplied from saliva. The following equation shows the reaction: Ca5(PO4)3OH(s) 5Ca2+(aq) + 3PO43(aq) + OH(aq) At equilibrium, the concentration of OH(aq) is 2 104 mol dm3. What is the value of Kc? A. 2 104 mol dm3 B. 1.20 1010 mol3 dm9 C. 2.16 1025 mol9 dm27 D. 4.32 1029 mol9 dm27



98 At a certain temperature, the equilibrium constant, Kc, for the reaction CO(g) + Cl2(g) COCl2(g) is 0.41 mol1 dm3. In an experiment, 0.4 mol of CO(g) was mixed with 0.2 mol of Cl2(g) in a 3.0 dm3 container. What is the equilibrium concentration of COCl2(g)? A. 2.64 mol dm3 B. 6.67 102 mol dm3 C. 1.01 102 mol dm3 D. 3.37 103 mol dm3

99 Consider the following equilibrium: SO2Cl2(g) SO2(g) + Cl2(g) In an experiment, 13.5 g of SO2Cl2(g) was introduced into a 4 dm3 container and allowed to reach equilibrium with SO2(g) and Cl2(g). At equilibrium, 0.069 mol of Cl2(g) was found in the reaction mixture. What is the equilibrium constant of the reaction? A. 0.0384 mol dm3 B. 0.0768 mol dm3 C. 2.23 mol dm3 D. 3.34 mol dm3

100 At 248C, the equilibrium constant, Kc, for the reaction SbCl3(g) + Cl2(g) SbCl5(g) is 40 mol1 dm3. In an experiment, 0.28 mol of SbCl3(g) was mixed with 0.16 mol of Cl2(g) in a 2.5 dm3 container and allowed to reach equilibrium with SbCl5(g). What is the equilibrium concentration of SbCl3(g) in the mixture? A. 1.78 104 mol dm3 B. 0.0657 mol dm3 C. 0.155 mol dm3 D. 40.2 mol dm3

101 In a Haber Process, x mol of N2(g) and y mol of H2(g) are introduced into a V dm3 container and allowed to reach equilibrium with NH3(g). At equilibrium, 2z mole of NH3(g) is found in the reaction mixture. What is the equilibrium constant for the reaction?



A. Kc = 322

)3)((4

zyzxVz

B. Kc = )3)((2

zyzxzV

C. Kc = 223

4)3)((

Vzzyzx

D. Kc = zVzyzx

2)3)((

102 Consider the following equilibrium: Fe3+(aq) + SCN(aq) FeSCN2+(aq) In an experiment, 50 cm3 of a 1.0 mol dm3 Fe(NO3)3(aq) solution was mixed with 50 cm3 of a 1.0 mol dm3 KSCN(aq) solution. At equilibrium, 1.94 g of FeSCN2+(aq) was found in the reaction mixture. What is the equilibrium constant for the reaction? A. 0.390 mol1 dm3 B. 0.641 mol1 dm3 C. 0.781 mol1 dm3

D. 1.56 mol1 dm3

103 Chemical A ionizes in water and reaches an equilibrium: A(aq) 2B(aq). The equilibrium constant for the ionization is 180 mol dm3. Originally there is 0.97 M of A. What is the equilibrium concentration of B? A. 0.02 mol dm3 B. 0.07 mol dm3 C. 0.95 mol dm3 D. 1.90 mol dm3

104 At 25C, the equilibrium constant, Kc, for the reaction below is greater than 1. A(g) + B(g) C(g) + D(g) Which of the following statements concerning the above reaction are correct? (1) It is a homogeneous equilibrium. (2) At equilibrium, the product of the concentrations of C and D is larger than that of

A and B in the reaction mixture. (3) Raising the temperature can raise the Kc. A. (1) and (2) only



B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

105 Solid sodium hydrogencarbonate undergoes thermal decomposition to give sodium carbonate, carbon dioxide, and steam. Which of the following information are required for calculating the equilibrium constant, Kc? (1) [CO2(g)]eqm (2) [H2O(g)]eqm (3) [Na2CO3(s)]eqm A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

106 It is known that 1 mol of A, 2 mol of B, 1 mol of C and 1 mol of D are present in the equilibrium mixture for the following reaction in a 1 dm3 container. A(g) + B(s) C(g) + D(g) What is the equilibrium constant for the above reaction?

A. 21

B. 1 mol dm3

C. 23 mol dm3

D. 2

107 Given:

Reaction Equilibrium constant 2NO2(g)

N2O4(g) K1

N2O4(g) K2NO2(g)

2

Which of the following statements is/are correct? (1) K1 is the reciprocal of K2. (2) K1 is equal to K2.



(3) K2 is the reciprocal of K1.

C. (1) and (3) only D. (2) and (3) only

c

brium equation is written in reverse or not. n temperature. l dm3.


A. (1) only B. (2) only

108 Whi h of the following statements concerning equilibrium constant is/are INCORRECT? (1) It remains constant even if the equili(2) Its value depends o(3) Its unit must be mo A. (1) only B. (2) only

109 Consider the following reaction: 2SO2(g) + O2(g) 2SO3(g) In an experiment, 0.05 mol of SO2(g) and 0.03 mol of O2(g) were introduced into a 1dm

ner and allowed to reach equilibrium with SO3(g). At equilibrium, the

as 0.04 mol dm3. What is the equilibrium constant of the

C. 400 mol1 dm3 D. 1600 mol1 dm3

3 contaiconcentration of SO3(g) wreaction? A. 21.3 mol1 dm3 B. 26.7 mol1 dm3

110 At a given temperature, the equilibrium constant, Kc, for the reaction PCl5(g) PCl3(g) + Cl2(g) is 0.106 mol dm3. In an experiment, 1.0 103 mol of PCl5(g) was introduced into a

3(g) and Cl2(g). What is PCl5(g) in the mixture?

C. 3.04 103 mol dm3

250 cm3 container and allowed to reach equilibrium with PClthe equilibrium concentration of A. 1.40 104 mol dm3 B. 9.65 104 mol dm3



D. 3.86 103 mol dm3

111 Consider the following equilibrium: 4HCl(g) + O2(g) 2Cl2(g) + 2H2O(g) In an experiment, 0.8 mol of HCl(g) and 0.5 mol of O2(g) were introduced into a 1dm

to reach equilibrium with Cl2(g) and 2H2O(g). At

f moles of HCl(g) was 0.4 mol. What is the equilibrium ction?

3

C. 0.25 D. 0.156 mol1 dm3

3 container and allowed equilibrium, the number oconstant for this rea A. 6.40 mol dm B. 4.00

112 At a given temperature, the equilibrium constant, Kc, for the reaction N2(g) + O2(g) 2NO(g) is 13. In a certain experiment, 0.35 mol of N2(g) and 0.30 mol of O2(g) were intro ced er uWhat were the equilibrium concentrations of all the species in the mixt

[N

du into a 500 cm3 contain and allowed to reach eq ilibrium with NO(g). ure?

2(g)]eqm (mol dm3) [O2(g)]eqm (mol dm3) [NO(g)]eqm (mol dm3)A. 0.73 0.83 1.43 B. 0.29 0.19 0.42 C. 0.29 0.19 0.83 D. 0.73 0.19 0.42

x with

concentration of ethanoic acid was 0.012 mo concentrations of ethanol and ethyl ethanoate in the mixtur

[C

113 In an experiment, 20 cm3 of 0.05 mol dm3 ethanoic acid was heated under reflu30 cm3 of 0.03 mol dm3 ethanol to give ethyl ethanoate. The equilibrium

l dm3. What were the equilibriume?

2H5OH(l)]eqm (mol dm3) [CH3COOC2H5(l)]eqm (mol dm3) A. 0.01 0.01 B. 0.008 0.01



C. 0.008 0.008 D. 0.01 0.008

um with NO2. The equilibrium concentration of NO2 was is the equilibrium constant for the reaction?

3

C. 1.38 D. 1.81 mol1 dm3

eated in a 1 dm3 container at 300C. At l5(g) was dissociated into PCl3(g) and Cl2(g). What is the f gases at equilibrium?

C. 1.5 mol D. 2.0 mol

ol of N2O4(g) was introduced into a 1 dm3 container and

114 In an experiment, 0.98 mol of N2O4 was introduced into a 2 dm3 container and allowed to reach equilibri0.4 mol dm3. What A. 0.55 mol dm B. 0.73

115 In an experiment, 1.0 mol of PCl5(g) was hequilibrium, 50% of PCtotal number of moles o A. 0.5 mol B. 1.0 mol

116 In an experiment, 1.0 mallowed to reach equilibrium with NO2(g). N2O4(g) 2NO2(g)

2O4(g) was converted to NO2(g). Calculate the value of Kc

C. 32.4 mol dm3 D. 90.0 mol dm3

3 OOH(l) were

H3COOH(l)

At equilibrium, 90% of Nfor this reaction. A. 8.1 mol dm3 B. 9.0 mol dm3

117 In an experiment, 3.0 mol of CH CH2OH(l) and 4.0 mol of CH3Cintroduced into a 1 dm3 container and allowed to reach equilibrium. CH3CH2OH(l) + C CH3COOCH2CH3(l) + H2O(l)

mol of CH3COOCH2CH3(l) was formed. What is the value of Kc At equilibrium, 2.2 for this reaction?



A. 0.40 B. 1.53 C. 2.48

D. 3.36

2(g) + S(s)

118 At 90C, the equilibrium constant, Kc, for the reaction H H2S(g) is 6.8

nd 1 mol of S(s) are heated to 90C in a 2 dm3 container. les of H2S(g) at equilibrium?

C. 0.090 mol D. 0.191 mol

to a ivided iron. The system later reached equilibrium and 0.9

mol of ammonia was formed are the number of moles of N2(g) and H2(g) at equilibrium respectively?

102. If 3 mol of H2(g) aWhat is the number of mo A. 0.045 mol B. 0.054 mol

119 In an experiment, 1.0 mol of N2(g) and 3.0 mol of H2(g) were introduced inclosed vessel with finely d

. What

N2(g) H2(g) A. 0.10 0.30 B. 0.55 1.65 C. 0.45 1.35 D. 0.10 0.10

rium mixture at a certain temperature contains 7.6 103 M of PCl5, 2.1 2 M of Cl2. What is the value of Kc for the following

Cl5

120 An equilib102 M of PCl3, and 2.09 10reaction?P (g) PCl3(g) + Cl2(g) A. 4.40 104 mol dm3 B. 4.40 104 mol2 dm6 C. 5.78 102 mol dm3

D. 5.78 102 mol2 dm6

121 Consider the following reaction: CH3COOH(aq) H+(aq) + CH3COO(aq) Kc = 0.304 mol dm3



Equal volumes of 1 M HCl(aq) and 1 M CH3COONa(aq) are mixed together. ion of CH3COOH(aq) after mixing the solutions and attaining

C. 3.289 M D. No CH3COOH(aq) will be formed after mixing.

Calculate the concentratequilibrium. A. 0.234 M B. 0.822 M

122 Consider the following reaction: CO(g) + H2O(g) H2(g) + CO2(g) Suppose 1 M of CO(g) and 1 M of H2O(g) are placed inside a reaction tank initially.

m constant at a certain temperature is 4.24, find the n of CO2(g) at that temperature.

C. 1.944 M D. It cannot be determined.

The value of equilibrium constant for the reaction H2(g) + I2(g)

Given that the equilibriuequilibrium concentratio A. 0.673 M B. 1.000 M

123 2HI(g) is 25 at

1100C. From m below, calculate the equilibrium concentration of HI(g).

C. 7.15 D. 14.3

the diagra

A. 0.87 B. 1.75

[H2(g)]

[I2(g)]

Time

Con

cent

ratio

n (m

ol d

m3

)



124 For the following reaction: 2X(g) + Y (g) 2 2Z(g), the value of equilibrium constant is 0.2 m 1 dm3. Wol hat is

librium constant for the reaction Z(g) the value of equi X(g) + 21 Y2(g)?

A. 0.45 23

21

dmmol

B. 2.24 23

21

dmmol

C. 5 23

21

dmmol

D. 10 23

21

dmmol

125 For the following reaction: W(g) + X(g) Y(g) + Z(g) 0.6 mol of W(g) and 0.6 mol of X(g) were mixed in a container at a certain

librium, Y(g) was found to be 0.1 mol. What is the value of t for this reaction?

C. 5 D. 25

temperature. At equiequilibrium constan A. 0.04 B. 0.25

126 The value of equilibrium constant for the following reaction is 6.60. X(g) + 2Y(g) 3Z(g)

X(g) is 2.0 mol dm3 and concentration of Y(g) is

of Z(g)?

C. 3.30 mol dm3 D. 6.60 mol dm3

At equilibrium, the concentration of1.0 mol dm3. What is the concentration A. 1.10 mol dm3 B. 1.88 mol dm3

127



Consider the equilibrium reaction below: 2A(aq) + B(aq) 4C(aq) If the value of the equilibrium constant for this reaction is equal to 1.0 mol dm3 at a certain temp e fo ilibri is possible?

[A(aq) l dm

erature, which of th llowing sets of equ um concentrations

]/mo 3 [B(aq)]/mol dm3 [C(aq) l dm]/mo 3 A. 1.0 1.0 1.0 B. 1.0 2.0 1.0 C. 2.0 1.0 1.0 D. 2.0 1.0 2.0

128 Consider the following equilibrium reaction: N2(g) + 3H2(g) 2NH3(g)

the value f the eq ilibrium cone v lue of the equilibrium

If o u stant for the reaction is 0.105 mol2 dm6 at 50C, what is th a constant at the same temperature for the reaction:

21 N (g) + 2 2

3 H (g) 2 NH3(g)?

C. 0.324 mol1 dm3 D. 9.52 mol1 dm3

A. 0.0110 mol1 dm3

B. 0.105 mol1 dm3

129 Consider the following equilibrium reaction: 2SO2(g) + O2(g) 2SO3(g) At 298 K, 1.00 mol of SO2(g) and 0.80 mol of O2(g) were allowed to react in a sealed

3. At equilibrium, 0.40 mol of SO2(g) was remained. What is erature?

C. 135.4 mol1 dm3 338.7 mol1 dm3

vessel of volume 30.0 dmthe value of Kc at this temp A. 4.5 mol1 dm3 B. 90.2 mol1 dm3

D.

130 Consider the following equilibrium reaction at 298 K: Cu(s) + 2Ag+(aq) Cu2+(aq) + 2Ag(s)



If the concentration of Cu2+(aq) is very much more than Ag+(aq) at equilibrium, which f th ll most probable value of the equilibrium constant for this

C. 1.1 101 D. 2.2 104

o e fo owing is thereaction? A. 8.9 109 B. 1.4 102

131 The value of the equilibrium constant for the reaction: H2(g) + I2(g) 2HI(g) i43.5 at a certain temperature. Calculate the

s equilibrium concentration of I2(g) when

f H2(g) were found to be present at equilibrium in a perature.

C. 5.75 102 mol dm3 D. 1.15 101 mol dm3

2.00 mol of HI(g) and 0.80 mol ocontainer of 3.00 dm3 at this tem A. 3.83 103 mol dm3 B. 5.75 103 mol dm3

132 Consider the hydrogenation of ethene below: C2H4(g) + H2(g) C2H6(g) The value of the equilibrium constant for the reaction is 0.99 mol1 dm3 at a certain temperature. If the initial concentrations of ethene gas and hydrogen gas are 0.335

3, what is the equilibrium concentration of C2H4(g) at

C. 0.425 mol dm3 D. 1.771 mol dm3

mol dm3 and 0.526 mol dmthis temperature? A. 0.101 mol dm3 B. 0.236 mol dm3

133 Consider the following equilibrium reaction: N2(g) + O2(g) 2NO(g) When 0.92 mol of N2(g) and 0.51 mol of O2(g) are heated in a 5.0 dm3 sealed onta r nally 98.9% of N2(g) is remained. What is the value of the

r the above reaction at this temperature? c ine at 2200 K, fiequilibrium constant fo A. 2.25 104



B. 8.79 104 C. 1.11 101

D. 2.22 101

Section 42.5 134 In the determination of the equilibrium constant for the reaction: Fe3+(aq) + SCN(aq) FeSCN2+(aq) Which of the following experimental methods can be used to find out the equilibrium

nsity of mixture by colorimeter of equilibrium mixture by an electronic balance


f ecide whether or not

the s t one optio ing to the following table:

ation

correct ment.

C. The 1st statement is false but the 2nd statement is true. h statements are false.

concentrations of all chemical species in this reaction? (1) Titration using acidified potassium dichromate solution (2) Measuring the inte(3) Weighing the mass A. (1) only B. (2) only

Each question below consists of two separate statements. Decide whether each othe two statements is true or false; if both are true, then d

econd statement is a correct explanation of the first statement. Then selecn from A to D accord

A. Both statements are true and the 2nd statement is a correct explanof the 1st statement.

B. Both statements are true and the 2nd statement is NOT aexplanation of the 1st state

D. Bot

Section 42.1 135 Equilibrium constant does not depend on the concentrations of reactants and

Equilibrium constant is dependent on temperature.

products.



Section 42.2 136 The reaction: N2(g) + O2(g) 2NO(g) is a homogenous equilibrium.

All reactants and products are in the same phase.

o constant of the reaction: Ni(CO)4(g)

137 The expressi n for the equilibrium

Ni(s) + 4CO(g) is

eqm4

4eqm

)]g()CO(Ni[)]g(CO[

.

liquids in heterogeneous equilibria do not appear in the expression of Kc.

The concentrations of solids and

Section 42.3 138 The larger the Kc value, the faster is the reaction to reach equilibrium.

equilibrium concentrations of products are much higher than that of reactants.

If a reaction has a large Kc value, the

139 The larger the equilibrium constant, the

r is the reaction rate. If the equilibrium constant is larger than

1, the product side is favoured. highe

Equilibrium constant depends on mperature.

Equilibrium constant is found by doing experiments only.

140

te

hemistry: Chapter 43 The effect of changes in concentration and temperature on libria

Cchemical equi Section 43.1 141 The following equilibrium was originally established in a 1 dm3 sealed container at a certain temperature. PCl5(g) PCl3(g) + Cl2(g) Kc = 4.16 102 mol dm3



However, the equilibrium has been disturbed and there are now 0.45 mol of PCl5(g),

corree point when the equilibrium was disturbed will

will be formed. ) m position will shift to the left.


0.15 mol of PCl3(g) and 0.15 mol of Cl2(g). Which of the following statements is/arect?

(1) The reaction quotient, Qc, at thbe greater than Kc.

(2) More PCl3(g) (3 The equilibriu A. (1) only B. (2) only

142 Consider the following equilibrium reaction: X(g) Y(g) + Z(g) What change will occur when there is a change causing the reaction quotient, Qc, to

constant, Kc, at constant temperature?

C. More Z is formed. D. No change in the concentrations of X, Y and Z.

be greater than the equilibrium A. More X is formed. B. More Y is formed.

143 Consider the following reaction: Co2+(aq) + 4Cl(aq) CoCl42(aq) The concentrations of Co2+(aq), Cl(aq) and CoCl42(aq) at a particular moment are x

3 y d 3 and z mol dm3 respectively. What is the reaction quotient for the above reaction at that particular moment? mol dm , mol m

A. xyzcQ

B. 4cQ xyz

C. z

xy4cQ

D. zxycQ

144



Consider the following chemical equilibrium: Cr2O72(aq) + H2O(l) 2CrO42(aq) + 2H+(aq) Whi h of the following statement(s) is/are correct? c

es orange when dilute NaOH(aq) is added to the mixture. es yellow when dilute H2SO4(aq) is added to the mixture.


(1) Both Cr2O72(aq) and CrO42(aq) are present in the reaction mixture. (2) The solution becom(3) The solution becom A. (1) only B. (2) only

145 Consider the following equilibrium reaction: N2(g) + 3H2(g) 2NH3(g) W n ex ra nitrogen gas is added to thhe t e closed container, which of the following han w Kc at 298 K?

C. The value of Kc remains unchanged. D. The change cannot be determined.

)

c ges ould happen on the value of A. The value of Kc increases. B. The value of Kc decreases.

146 Consider the following reaction that has attained dynamic equilibrium: Br2(aq) + H2O(l H+(aq) + Br(aq) + HOBr(aq)

aOH(aq) are added x

ur of the mixture becomes darker. ur of the mixture becomes paler.

C. Steam is given out. D. None of the above.

Which of the following would be observed when a few drops of Nto the mi ture? A. The pale yellow colo B. The pale yellow colo

147 Consider the following reaction that has attained dynamic equilibrium: Cr2O72(aq) + H2O(l) 2CrO42(aq) + 2H+(aq) Cr2O a ur. Which of the

dded to the mixture? ange.

lution becomes nearer to yellow.

72( q) is orange in colour and CrO42(aq) is yellow in colo

following would be observed when a few drops of HCl(aq) are a A. The colour of the solution becomes nearer to or B. The colour of the so



C. The colour of the solution remains unchanged. D. None of the above.

148 Consider the following equilibrium reaction: H2S(aq) 2H+(aq) + S2(aq)

H2S(aq) would decrease by adding

C. SO42(aq). D. Na+(aq).

The concentration of A. H+(aq). B. OH(aq).

149 Consider the following equilibrium reaction: 2CrO42(aq) + 2H+(aq) Cr2O72(aq) + H2O(l)

ellow by adding

solution. lution.


r le in water and an equilibrium is established as

The colour of the solution turns y(1) dilute hydrochloric acid. (2) sodium carbonate (3) sodium sulphite so A. (1) only B. (2) only

150 Calcium ca bonate is sparingly solubfollows: CaCO3(s) Ca2+(aq) + CO32(aq) Which of the following chemicals would make calcium carbonate more soluble in

above equilibrium? n

lution


water when added to the(1) Sodium carbonate solutio(2) Dilute nitric acid (3) Calcium nitrate so A. (1) only B. (2) only



151 Consider the following equilibrium reaction: Br2(aq) + H2O(l) HOBr(aq) + H+(aq) + Br(aq)

c se the colour of bromine water to become

cid sodium hydroxide solution ium bromide


Whi h of the following changes would caupaler? (1) Addition of dilute hydrochloric a(2) Addition of dilute (3) Addition of potass A. (1) only B. (2) only

152 Consider the following equilibrium reaction: Br2(aq) + H2O(l) HOBr(aq) + H+(aq) + Br(aq)

H+ of the following correctly s

C. The mixture turns from pale yellow to yellow. D. The mixture turns from yellow to pale yellow.

If (aq) is added to the above reaction mixture, which describe the colour change of the mixture? A. The mixture turns from colourless to yellow. B. The mixture turns from yellow to colourless.

153 The value of the equilibrium constant for the reversible reaction: 2HI(g) H2(gI

) + he

t this temperature are 2.50 103 M, 8.00 103 M and 4.10 105 M

correct?

hange.

D. The system is in equilibrium and the concentrations of all chemical species are equal.

2(g) is 2.02 102 at 40C. If the concentrations of HI(g), H2(g) and I2(g) in tmixture arespectively, which of the following statements concerning the above system is

A. The system is in equilibrium and the concentrations of all chemical specieswill not c

B. The system is not in equilibrium and the equilibrium position will shift to the left.

C. The system is not in equilibrium and the equilibrium position will shift to the right.



154 Consider the following system which is in equilibrium at a certain temperature: 2CO(g) + O2(g) 2CO2(g) If some CO(g) is added to the system, which of the following statements is correct?

C. There is a change in concentrations for both reactants and products. D. There is no change in concentrations for both reactants and products.

a closed container, it reacts according to

(l)

A. There is a change in concentrations for the reactants only. B. There is a change in concentration for the product only.

155 When carbon dioxide dissolves in water inthe equation: CO2(g) + H2O H+(aq) + HCO3(aq)

n dioxide gas escapes from the reaction mixture at

C. The pH of the reaction mixture will remain constant. pH of the reaction mixture will become zero.

What will happen if some carboequilibrium? Given that pH = log[H+(aq)]. A. The pH of the reaction mixture will increase. B. The pH of the reaction mixture will decrease.

D. The

Section 43.2 156 Consider the following equilibrium system: Ag+(aq) + Fe2+(aq) Ag(s) + Fe3+(aq) What change will occur when there is a change causing the reaction quotient, Qc, to

tant, Kc?

C. More Ag(s) is formed. D. No change in the amount of Ag+(aq), Fe2+(aq), Ag(s) and Fe3+(aq).

tant of a reversible reaction is dependent on the

product(s).

be smaller than the equilibrium cons A. More Ag+(aq) is formed. B. More Fe2+(aq) is formed.

157An equilibrium cons(1) concentration(s) of reactant(s). (2) temperature. (3) concentration(s) of A. (1) only



B. (2) only C. (1) and (3) only

D. (2) and (3) only

c n equilibrium system is heated?

rd reaction is increased. ) reaction is increased.

is

C. (2) and (3) only D. (1), (2) and (3)

ing changes will NOT change the value of Kc of an equilibrium

C. (2) and (3) only D. (1), (2) and (3)

c value and equilibrium po the CH4 + 4NO

158Whi h of the following statements are correct if a(1) The rate of forwa(2 The rate of backward (3) Kc increased. A. (1) and (2) only B. (1) and (3) only

159 Which of the followreaction? (1) Temperature (2) Pressure (3) Concentration A. (1) and (2) only B. (1) and (3) only

160 When there is a decrease in temperature, what are the changes in K

sition for following equilibrium reaction? (g) (g) 2N2(g) + CO2(g H = ve ) + 2H2O(g) Kc value Change in position equilibrium

A. increases to the right

B. increases to the left

C. decreases to the right

D. decreases to the left

at a certain temperature: 161 Consider the following reaction at equilibrium



H BF3N (3 s) NH3(g) + BF3(g) when the mass of H3NBF3 (s) is doubled, A. the amount of NH3(g) and BF3(g) at equilibrium is halved. B. the equilibrium constant will not be affected. C. the amounts of NH3(g) and BF3(g) at equilibrium is increased.

D. the amount of H3NBF3(s) will then start decreasing.

162 For the following reaction: Cu(OH)2(s) Cu2+(aq) + 2OH(aq) H = +ve

increased by

) in dilute hydrochloric acid. ) in dilute sodium hydroxide solution.

C. (2) and (3) only D. (1), (2) and (3)

The equilibrium concentration of Cu2+(aq) would be (1) increasing the temperature. (2 add g a few drops of(3 add g a few drops of A. (1) and (2) only B. (1) and (3) only

163 Consider the following chemical equilibrium: A(aq) + B(aq) C(aq) + D(aq) Upon a change in temperature, which of the following would probably happen?

) h tions of reactants. ) h tions of products.

C. (2) and (3) only D. (1), (2) and (3)

following would occur upon an increase in temperature?

(1) A change in the value of Kc. (2 A c ange in concentra(3 A c ange in concentra A. (1) and (2) only B. (1) and (3) only

164 For a reversible chemical reaction with a negative enthalpy change, which of the

A. The value of Kc decreases and the equilibrium position of the system shifts to the left.

B. The value of Kc decreases and the equilibrium position of the system shifts to the right.



C. The value of Kc increases and the equilibrium position of the system shifts to the left.

D. The value of Kc increases and the equilibrium position of the system shifts to the right.

c re necessary for maintaining the state of

mount of catalyst in the system on for both reactants and products


165 Whi h of the following conditions is/achemical equilibrium? (1) Keeping a constant temperature (2) Keeping the same a(3) Keeping the same concentrati A. (1) only B. (2) only

166 Consider the following equilibrium reaction: 2H2S(g) 2H2(g) + S2(g) H = +170 kJ mol1 Whic of the f librium position is correct if t ture of the system

Effect o of K

h following concerning the e fect on the value of Kc and the equihe tempera is increased?

n the value c Effect o ositionn the equilibrium p

A. Increases Shifts to the left

B. Increases Shifts to the right

C. Decreases Shifts to the left

D. Decreases Shifts to the right

lo n concentrations of the reactant and products with time for the reversible reaction: C(aq)

167 The fol wing graph shows the change i

A(aq) + B(aq) H = +ve



Which of the following changes is done to the system at time t? A. Adding a small amount of C(aq) B. Removing some of C(aq) C. Increase in temperature D. Decrease in temperature

168 Consider the following equilibrium reaction: 4HCl(g) + O2(g) 2Cl2(g) + 2H2O(g) H = +ve Which of the following changes will cause a shift in the equilibrium position of the above reaction? (1) Adding Cl2(g) (2) Removing O2(g) (3) Adding a catalyst A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

Section 43.3 169 Consider the following equilibrium system: 2H2S(g) 2H2(g) +S2(g) H = +ve Which of the following changes will shift the equilibrium position of the reaction? (1) Introducing H2 gas into the system (2) Increasing the temperature of the system at constant pressure (3) Increasing the volume of the system at constant temperature

Con

cent

ratio

n (m

ol d

m3

) A(aq)

B(aq)

C(aq)

Time



A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

170 Consider the following equilibrium system: N2(g) + 3H2(g) 2NH3(g) H = ve Which of the following changes will occur if the temperature of the system increases at constant pressure? (1) The equilibrium position will shift to the left. (2) The value of Kc will increase. (3) The yield of NH3(g) will decrease. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

171 Consider the following equilibrium system: HCO3(aq) OH(aq) + CO2(g) A few drops of phenolphthalein are added as an indicator. At equilibrium, the reaction mixture is colourless. Which of the following changes will cause the reaction mixture to appear pink in colour? (1) Adding more drops of indicator (2) Reducing the pressure of the system (3) Removing CO2(g) from the system A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

172 Consider the following equilibrium system: 2SO2(g) + O2(g) 2SO3(g) H = ve Which of the following changes will decrease the value of equilibrium constant? (1) Addition of a catalyst (2) Increasing the temperature of the system at constant pressure



(3) Decreasing the volume of the system at constant temperature A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

173 Consider the following equilibrium system: N2O4(g) 2NO2(g) If the above equilibrium is disturbed by adding some NO2(g), which of the following statements is/are correct? (1) The concentration of N2O4(g) will increase, then remain constant. (2) The equilibrium constant will decrease. (3) The equilibrium position will shift to the left. A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

174 Consider the following equilibrium system: HCOOH(aq) HCOO(aq) + H+(aq) If a small amount of HCl(aq) is added to the reaction mixture, which of the following changes will occur? (1) The concentration of H+(aq) will remain unchanged. (2) The concentration of HCOO(aq) will decrease. (3) The concentration of HCOOH(aq) will increase. A. (1) and (2) only B. (1) and (3) only C (2) and (3) only D. (1), (2) and (3)

175 Which of the following changes will NOT shift the equilibrium position of the reaction below? H2(g) + I2(g) 2HI(g) H = ve (1) Increase in temperature (2) Increase in volume



(3) Increase in concentration of HI(g) A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

176 Consider the following equilibrium system at constant pressure. 2SO2(g) + O2(g) 2SO3(g) H = ve Which of the following statements is/are correct? (1) An increase in temperature favours the backward reaction. (2) An increase in concentration of SO3(g) shifts the equilibrium position to the

right. (3) An increase in temperature decreases the value of Kc. A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

177 Consider the following equilibrium system at constant pressure: 2CHClF2(g) C2F4(g) + 2HCl(g) H = +ve Which of the following statements are correct? (1) An increase in temperature shifts the equilibrium position to the product side. (2) An increase in concentration of C2F4(g) shifts the equilibrium position to the

reactant side. (3) A decrease in concentration of HCl(g) shifts the equilibrium position to the

product side. A. (1) and (2) only B. (1) and (3) only C (2) and (3) only D. (1), (2) and (3)

178 Which of the following methods are beneficial to the industrial production of nitric acid? 3NO2(g) + H2O(l) 2HNO3(aq) + NO(g) (1) Addition of nitrogen dioxide to the equilibrium mixture



(2) Removal of nitrogen monoxide once it is formed (3) Increasing the pressure of the system at constant temperature A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

179 Which of the following changes will make the value of Qc smaller than that of Kc for the equilibrium reaction below? NH4HS(s) NH3(g) + H2S(g) (1) Addition of NH3(g) to the equilibrium mixture (2) Removal of NH3(g) from the equilibrium mixture (3) An increase in the volume of the system at constant temperature A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

180 Consider the following equilibrium system: H2(g) + I2(g) 2HI(g) What will be the change in the equilibrium position if the pressure of the system is increased? A. The equilibrium position will shift to the left. B. The equilibrium position will shift to the right. C. The equilibrium position will remain unchanged. D. The change in equilibrium position cannot be determined.

181 When there is an increase in temperature, what are the changes in Kc value and equilibrium position for the following equilibrium reaction? I2(g) + C5H8(g) C5H6(g) + 2HI(g) H = +ve

Kc value Change in equilibrium position A. Increases Shifts to the left B. Increases Shifts to the right C. Decreases Shifts to the left D. Decreases Shifts to the right



182 At high temperature, calcium carbonate decomposes to form calcium oxide and carbon dioxide according to the following equation: CaCO3(s) CaO(s) + CO2(g) H = +ve Which of the following statements is/are correct? (1) The addition of carbon dioxide at equilibrium will produce more calcium

carbonate. (2) A decrease in temperature will produce more carbon dioxide. (3) An increase in pressure at equilibrium will produce more calcium carbonate. A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

183 Which of the following actions will cause the equilibrium position of the reaction to shift to the right? NH4NO3(s) N2O(g) + 2H2O(g) A. Adding H2O(g) to the equilibrium mixture. B. Increasing the volume of the container by four times. C. Adding N2O(g) to the equilibrium mixture. D. Decreasing the volume of the container by four times.

184 Which of the following changes will make the value of Qc greater than that of Kc for the equilibrium reaction below? N2(g) + 3H2(g) 2NH3(g) H = ve (1) Adding a catalyst to the equilibrium mixture (2) Decreasing the pressure of the system at constant temperature (3) Removal of N2 from the system A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

185 Consider the following equilibrium system:



C(s) + CO2(g) 2CO(g) H = +ve Which of the following changes will shift the equilibrium position of the above reaction? (1) Decrease in pressure under constant temperature (2) Increase in temperature under constant pressure (3) Decrease in concentration of CO2(g) A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

186 Consider the following equilibrium system: N2O4(g) 2NO2(g) H = +ve Which of the following statements concerning the equilibrium reaction are correct? (1) When the pressure of the system is increased under constant temperature, the

colour of the reaction mixture will become lighter. (2) When the temperature of the system is increased at constant pressure, the colour

of the reaction mixture will become darker. (3) When some N2O4(g) is added to the system, the Qc is larger than the Kc. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

187 Consider the following equilibrium system: SiCl4(g) + 2H2(g) Si(s) + 4HCl(g) H = +ve The yield of Si(s) in the equilibrium system is increased by A. increasing the pressure of the equilibrium mixture at constant temperature. B. decreasing the temperature of the equilibrium mixture at constant pressure. C. passing hydrogen chloride through sodium hydroxide solution. D. removing hydrogen from the equilibrium mixture.

188 In which of the following equilibria will a decrease in volume (at constant temperature) increase the yield of product(s) of the reaction? A. CO(g) + H2(g) C(s) + H2O(g)



B. H2(g) + I2(g) 2HI(g) C. 4NH3(g) + 5O2(g) 4NO(g) + 6H2O(g) D. 2SO3(g) 2SO2(g) + O2(g)

189 Consider the following equilibrium system: H2(g) + I2(g) 2HI(g) Which of the following changes will alter the value of Kc? A. An increase in concentration of H2(g) B. An increase in concentration of I2(g) C. An increase in pressure of the system at constant temperature D. An increase in temperature of the system at constant pressure

190 Which of the following statements concerning an equilibrium system with an exothermic forward reaction is INCORRECT? A. An increase in temperature will decrease the value of Kc. B. An increase in temperature will shift the equilibrium position to the left. C. A decrease in temperature will decrease the value of Kc. D. A decrease in temperature will shift the equilibrium position to the right.

191 In which of the following equilibria will an increase in pressure (at constant temperature) does NOT affect the yield of product(s) of the reaction? A. Cl2(g) + 3F2(g) 2ClF3(g) B. PCl5(g) PCl3(g) + Cl2(g) C. H2(g) + I2(g) 2HI(g) D. 4HCl(g) + O2(g) 2H2O(g) + 2Cl2(g)

192 What will happen to [Cl(aq)]eqm in the following equilibrium if CoCl42(aq) is removed from the reaction mixture? Co2+(aq) + 4Cl(aq) CoCl42(aq) A. It will remain the same. B. It will decrease at first, then remain constant. C. It will increase at first, then remain constant. D. It will decrease at first, then increase.



193 Consider the following chemical equilibrium: I2(g) + H2(g) 2HI(g) H = 9.6 kJ mol1 Which of the following changes would shift the equilibrium position of the above reaction to the right? A. Increasing the pressure B. Decreasing the temperature C. Adding a catalyst to the system D. Removing hydrogen from the system

194 Consider the following chemical equilibrium: N2O4(g) 2NO2(g) H = +58 kJ mol1 Which of the following conditions would make the equilibrium mixture become darker? A. Increasing the pressure B. Decreasing the temperature C. Increasing the temperature but decreasing the pressure D. Decreasing the temperature but increasing the pressure

195 The forward reaction of the equilibrium system below is an endothermic reaction: A(g) + B(g) 2C(g) Its equilibrium constant is 1010 at 500 K. Which of the following changes would increase the concentration of C at equilibrium? A. Increasing the pressure B. Decreasing the temperature C. Adding reactant B(g) to the system D. Introducing a catalyst to the system

196 In which of the following cases would an increase in pressure and temperature produce more products?

A. X2(g) + Y2(g) Z2(g) H = +ve B. X2(g) + Y2(g) 3Z2(g) H = +ve C. X2(g) + Y2(g) Z2(g) H = ve D. X2(g) + Y2(g) 3Z2(g) H = ve



197 Consider the following equilibrium reaction: A(aq) + B(aq) C(aq) H = +ve Which of the following change(s) would produce more product C? (1) Increasing the temperature (2) Adding catalyst to the system (3) Increasing the pressure A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

198 Consider the following equilibrium reaction: 2NO2(g) N2O4(g) H = ve Which of the following changes would cause an increase in the value of equilibrium constant for this reaction? A. Adding a catalyst to the system B. Decreasing the pressure C. Decreasing the temperature D. Adding more NO2(g) to the equilibrium mixture

199 Which of the following equilibria would NOT be affected by a volume change at constant temperature? A. 2H2O(g) 2H2(g) + O2(g) B. PCl5(g) PCl3(g) + Cl2(g) C. O3(g) + NO(g) O2(g) + NO2(g) D. H3NBF3(s) NH3(g) + BF3(g)

200 Consider the following equilibrium reaction: 2N2O(g) + O2(g) 4NO(g) Which of the following changes will increase the amount of NO(g) in the equilibrium mixture? (1) Adding N2O(g) (2) Removing O2(g) (3) Decreasing the volume of the container



A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

201 The value of the equilibrium constant for the dissociation of I2(g) is 3.76 105 mol dm3 at 1000 K. The equation for the dissociation is as follows: I2(g) 2I(g) After a certain time interval, 1.00 mol of I2(g) and 5.00 103 mol of I(g) were found in a 2.00 dm3 sealed flask. Which of the following statements is correct? A. The system is in equilibrium at 1000 K. B. The system is not in equilibrium at 1000 K and the equilibrium position will

shift to the left. C. The system is not in equilibrium at 1000 K and the equilibrium position will

shift to the right. D. The system is not in equilibrium at 1000 K and the equilibrium can be

attained by increasing the temperature of the system.

202 In which of the following reactions will the equilibrium position remain unchanged when the pressure on the system is increased by decreasing the volume of the container? A. C(s) + O2(g) CO2(g) B. CaCO3(s) CaO(s) + CO2(g) C. 3H2(g) + N2(g) 2NH3(g) D. 2H2(g) + O2(g) 2H2O(g)

203 The equation for the dissociation of NH4Cl(s) is as follows: NH4Cl(s) NH4+(aq) + Cl(aq) H = +ve Which of the following changes will cause a shift in the equilibrium position of the above system to the right? A. Dissolving sodium chloride solid in the reaction mixture B. Increasing the pressure of the system C. Increasing the temperature of the system D. Decreasing the temperature of the system



204 Consider the dissociation of water: H2O(l) H+(aq) + OH(aq) The values of equilibrium constant is 1.00 1014 at 25C and 2.95 1014 at 40C. Which of the following statements is correct? A. An increase in temperature will cause a decrease in concentration of H+(aq). B. The dissociation of water molecules is endothermic. C. The concentration of H+(aq) is greater than that of OH(aq) at 40C. D. The equilibrium position lies mainly on the product side at 40C.

Section 43.4 205 3H2(g) + N2(g) 2NH3(g) H = 92 kJ mol1 Which of the following changes would increase the yield of ammonia at equilibrium? (1) Increasing the pressure (2) Decreasing the temperature (3) Using iron powder as catalyst A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

Each question below consists of two separate statements. Decide whether each of the two statements is true or false; if both are true, then decide whether or not the second statement is a correct explanation of the first statement. Then select one option from A to D according to the following table:

A. Both statements are true and the 2nd statement is a correct explanation of the 1st statement.

B. Both statements are true and the 2nd statement is NOT a correct explanation of the 1st statement.

C. The 1st statement is false but the 2nd statement is true. D. Both statements are false.

Section 43.1 206 Qc has the same unit as Kc. At equilibrium, Qc = Kc.



207 Qc and Kc always have the same value. Qc and Kc have the same expression

form.

Section 43.2 208 It is impossible to predict the effect of temperature change on the equilibrium position without knowing the enthalpy change of the reaction.

An increase in temperature favours an endothermic change of an equilibrium system.

209 If the reaction quotient is greater than the equilibrium constant, the equilibrium position shifts to the product side.

Reaction quotient can be calculated at any particular moment, not necessarily at equilibrium.

Section 43.3 210 For the equilibrium system: 4HCl(g) + O2(g) 2Cl2(g) + 2H2O(g). An Increase in pressure shifts the equilibrium position to the left.

Le Chteliers Principle states that when a chemical system at equilibrium is disturbed by a change in conditions, the equilibrium position will shift in a way that tends to counteract the change.

211 At a given temperature, a change in concentrations of the reactants or the products can alter Kc and Qc.

A change in concentrations of the reactants or the products can alter the equilibrium position.

212 When the concentrations of the reactants of an equilibrium system are changed, the value of Kc is changed.

According to Le Chteliers Principle, the equilibrium position will shift in a direction that tends to counteract the disturbances.



Section 43.4 213 Haber Process should be carried out at a low temperature to obtain a higher yield of ammonia.

Since the forward reaction in Haber Process is exothermic, a low temperature favours the formation of ammonia.

MCQ CE

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