# Chemical Equilibrium Test 4

Total Questions:50 Total Time: 75 Min

Remaining:

## Questions 1 of 50

Question:The vapour density of completely dissociated $$N{H_4}Cl$$ would be

Slight less than half that of $$N{H_4}Cl$$

Half that of $$N{H_4}Cl$$

Double that of $$N{H_4}Cl$$

Determined by the amount of solid $$N{H_4}Cl$$ in the experiment

## Questions 2 of 50

Question:A chemical reaction is at equilibrium when

Reactants are completely transformed into products

The rates of forward and backward reactions are equal

Formation of products is minimized

Equal amounts of reactants and products are present

## Questions 3 of 50

Question:In the chemical reaction $${N_2} + 3{H_2}$$ $$\Leftrightarrow$$$$2N{H_3}$$ at equilibrium point, state whether

Equal volumes of $${N_2}$$ and $${H_2}$$ are reacting

Equal masses of $${N_2}$$ and $${H_2}$$ are reacting

The reaction has stopped

The same amount of ammonia is formed as is decomposed into $${N_2}$$ and $${H_2}$$

## Questions 4 of 50

Question:For the reaction $$PC{l_3}(g) + C{l_2}(g)$$ \ [ \Leftrightarrow \) $$PC{l_5}(g)$$ the position of equilibrium can be shifted to the right by

Increasing the temperature

Doubling the volume

Addition of $$C{l_2}$$ at constant volume

Addition of equimolar quantities of $$PC{l_3}$$and $$PC{l_5}$$

## Questions 5 of 50

Question:If a system is at equilibrium the rate of forward to the reverse reaction is

Less

Equal

High

At equilibrium

## Questions 6 of 50

Question:In the above equilibrium system if the concentration of the reactants at $${25^o}C$$ is increased, the value of $${K_c}$$ will

Increase

Decrease

Remains the same

Depends on the nature of the reactants

## Questions 7 of 50

Question:At a given temperature, the equilibrium constant for reaction $$PC{l_5}(g)$$ $$\Leftrightarrow$$ $$PC{l_3}(g) + C{l_2}(g)$$ is $$2.4 \times {10^{ - 3}}$$. At the same temperature, the equilibrium constant for reaction $$PC{l_3}(g) + C{l_2}(g)$$ $$\Leftrightarrow$$ $$PC{l_5}(g)$$ is

$$2.4 \times {10^{ - 3}}$$

$$- 2.4 \times {10^{ - 3}}$$

$$4.2 \times {10^2}$$

$$4.8 \times {10^{ - 2}}$$

## Questions 8 of 50

Question:For the reaction $$C(s) + C{O_2}(g)$$ $$\Leftrightarrow$$ $$2CO(g)$$, the partial pressure of $$C{O_2}$$ and $$CO$$ are 2.0 and 4.0 atm respectively at equilibrium. The $${K_p}$$ for the reaction is

0.5

4

8

32

## Questions 9 of 50

Question:$$K$$ for the synthesis of $$HI$$ is 50. $$K$$ for dissociation of $$HI$$ is

50

5

0.2

0.02

## Questions 10 of 50

Question:The equilibrium constant $$({K_p})$$ for the reaction $$PC{l_5}(g) \to PC{l_3}(g) + C{l_2}(g)$$ is 16. If the volume of the container is reduced to one half its original volume, the value of $${K_p}$$ for the reaction at the same temperature will be

32

64

16

4

## Questions 11 of 50

Question:$$2N{O_2}$$ $$\Leftrightarrow$$$$2NO + {O_2};\,\,K = 1.6 \times {10^{ - 12}}$$ $$NO + \frac{1}{2}{O_2}$$ $$\Leftrightarrow$$$$N{O_2}K' = ?$$

$$K' = \frac{1}{{{K^2}}}$$

$$K' = \frac{1}{K}$$

$$K' = \frac{1}{{\sqrt K }}$$

None of these

## Questions 12 of 50

Question:The value of $${K_p}$$ for the following reaction $$2{H_2}S(g)$$ $$\Leftrightarrow$$$$2{H_2}(g) + {S_2}(g)$$ is $$1.2 \times {10^{ - 2}}$$ at $${106.5^o}C$$. The value of $${K_c}$$ for this reaction is

$$1.2 \times {10^{ - 2}}$$

$$< 1.2 \times {10^{ - 2}}$$

83

$$> 1.2 \times {10^{ - 2}}$$

## Questions 13 of 50

Question:Which statement for equilibrium constant is true for the reaction $$A + B$$ $$\Leftrightarrow$$$$C$$

Not changes with temperature

Increases with temperature

Changes with temperature

## Questions 14 of 50

Question:A reversible reaction $${H_2} + C{l_2}$$ $$\Leftrightarrow$$$$2HCl$$is carries out in one litre flask. If the same reaction is carried out in two litre flask, the equilibrium constant will be

Decreased

Doubled

Halved

Same

## Questions 15 of 50

Question:For the reaction $$2N{O_{2(g)}}$$ $$\Leftrightarrow$$$$2N{O_{(g)}} + {O_{2(g)}}$$,$${K_c} = 1.8 \times {10^{ - 6}}$$ at 185°C. At 185°C the Kc for $$N{O_{(g)}}$$+ $$\frac{1}{2}{O_{2(g)}}$$ $$\Leftrightarrow$$ $$N{O_{2(g)}}$$ is

$$1.95 \times {10^{ - 3}}$$

$$1.95 \times {10^3}$$

$$7.5 \times {10^2}$$

$$0.9 \times {10^6}$$

## Questions 16 of 50

Question:If for $${H_2}_{(g)} + \frac{1}{2}{S_{2(S)}}$$ $$\Leftrightarrow$$$${H_2}{S_{(g)}}$$ and $${H_{2(g)}} + B{r_{2(g)}}$$ $$\Leftrightarrow$$$$2HB{r_{(g)}}$$The equilibrium constants are K1 and K2 respectively, the reaction$$B{r_2}_{(g)} + {H_2}{S_{(g)}}$$ $$\Leftrightarrow$$$$2HB{r_{(g)}} + \frac{1}{2}{S_{2(S)}}$$ would have equilibrium constant

$${K_1}\; \times \;{K_2}$$

$${K_1}/{K_2}$$

$${K_2}/{K_1}$$

$$K_2^2/{K_1}$$

## Questions 17 of 50

Question:Consider the following reversible reaction at equilibrium, $$2{H_2}{O_{(g)}}$$ $$\Leftrightarrow$$ $$2{H_{2(g)}} + {O_{2(g)}}$$; $$\Delta H = 241.7\,kJ$$Which one of the following changes in conditions will lead to maximum decomposition of $${H_2}{O_{(g)}}$$

Increasing both temperature and pressure

Decreasing temperature and increasing pressure

Increasing temperature and decreasing pressure

Increasing temperature at constant pressure

## Questions 18 of 50

Question:For reaction, $$2A(g)$$ \ \Leftrightarrow \) $$3C(g) + D(s)$$, the value of $${K_c}$$will be equal to

$${K_p}(RT)$$

$${K_p}/RT$$

$$= {K_p}$$

None of these

## Questions 19 of 50

Question:In the reaction, $${A_2}(g) + 4{B_2}(g)$$ $$\Leftrightarrow$$ $$2A{B_4}(g)$$$$\Delta H < 0$$the formation of $$A{B_4}$$is will be favoured at

Low temperature, high pressure

High temperature, low pressure

Low temperature, low pressure

High temperature, high pressure

## Questions 20 of 50

Question:The equilibrium constant in a reversible reaction at a given temperature

Depends on the initial concentration of the reactants

Depends on the concentration of the products at equilibrium

Does not depend on the initial concentrations

It is not characteristic of the reaction

## Questions 21 of 50

Question:Pure ammonia is placed in a vessel at temperature where its dissociation constant ($$\alpha$$) is appreciable. At equilibrium

$${K_p}$$ does not change significantly with pressure

$$\alpha$$ does not change with pressure

Concentration of $$N{H_3}$$ does not change with pressure

Concentration of $${H_2}$$ is less than that of $${N_2}$$

## Questions 22 of 50

Question:For the system $$A(g) + 2B(g)$$ $$\Leftrightarrow$$$$C(g)$$, the equilibrium concentrations are 0.06 mole/litre 0.12 mole/litre 0.216 mole/litre. The $${K_{eq}}$$ for the reaction is

250

416

$$4 \times {10^{ - 3}}$$

125

## Questions 23 of 50

Question:A + B $$\Leftrightarrow$$ C + D. If finally the concentration of A and B are both equal but at equilibrium concentration of D will be twice of that of A then what will be the equilibrium constant of reaction.

4/9

9/4

1/9

4

## Questions 24 of 50

Question:If in the reaction $${N_2}{O_4} = 2N{O_2},\,\alpha$$ is that part of $${N_2}{O_4}$$ which dissociates, then the number of moles at equilibrium will be

3

1

$${(1 - \alpha )^2}$$

$$(1 + \alpha )$$

## Questions 25 of 50

Question:In the gas phase reaction, $${C_2}{H_4} + {H_2}$$ $$\Leftrightarrow$$ $${C_2}{H_6}$$, the equilibrium constant can be expressed in units of

$$litr{e^{ - 1}}\,mol{e^{ - 1}}$$

$$litre\,mol{e^{ - 1}}$$

$$mol{e^2}\,litr{e^{ - 2}}$$

$$mole\,litr{e^{ - 1}}$$

## Questions 26 of 50

Question:The rate constant for forward and backward reactions of hydrolysis of ester are $$1.1 \times {10^{ - 2}}$$ and $$1.5 \times {10^{ - 3}}$$ per minute respectively. Equilibrium constant for the reaction is $$C{H_3}COO{C_2}{H_5} + {H_2}O$$ $$\Leftrightarrow$$$$C{H_3}COOH$$$$+ {C_2}{H_5}OH$$

4.33

5.33

6.33

7.33

## Questions 27 of 50

Question:At a certain temp. 2HI $$\Leftrightarrow$$ H2 + I2 Only 50% HI is dissociated at equilibrium. The equilibrium constant is

0.25

1

3

0.5

## Questions 28 of 50

Question:When 3 mole of A and 1 mole of B are mixed in 1 litre vessel the following reaction takes place $${A_{(g)}} + {B_{(g)}}$$ $$\Leftrightarrow$$$$2{C_{(g)}}$$. 1.5 moles of C are formed. The equilibrium constant for the reaction is

0.12

0.25

0.5

4

## Questions 29 of 50

Question:In a reaction, reactant ‘A’ decomposes 10% in 1 hour, 20% on 2 hour and 30% in 3 hour. The unit of rate constant of this reaction is

$$se{c^{ - 1}}$$

$$mol\,\,litr{e^{ - 1}}\,se{c^{ - 1}}$$

$$litre\,\,mo{l^{ - 1}}\,se{c^{ - 1}}$$

$$litr{e^2}\,mo{l^{ - 2}}\,se{c^{ - 1}}$$

## Questions 30 of 50

Question:In the reaction $$PC{l_{5(g)}}$$ $$\Leftrightarrow$$ $$PC{l_{3(g)}}$$$$+ C{l_{2(g)}}.$$ The equilibrium concentrations of $$PC{l_5}$$ and $$PC{l_3}$$ are 0.4 and 0.2 mole/litre respectively. If the value of $${K_c}$$is 0.5 what is the concentration of $$C{l_2}$$ in moles/litre

2

1.5

1

0.5

## Questions 31 of 50

Question:In Haber process 30 litres of dihydrogen and 30 litres of dinitrogen were taken for reaction which yielded only 50% of the expected product. What will be the composition of gaseous mixture under the aforesaid condition in the end

20 litres ammonia, 25 litres nitrogen, 15 litres hydrogen

20 litres ammonia, 20 litres nitrogen, 20 litres hydrogen

10 litres ammonia, 25 litres nitrogen, 15 litres hydrogen

20 litres ammonia, 10 litres nitrogen, 30 litres hydrogen

## Questions 32 of 50

Question:When $$NaN{O_3}$$ is heated in a closed vessel, $${O_2}$$ is liberated and $$NaN{O_2}$$ is left behind. At equilibrium

Addition of $$NaN{O_3}$$ favours forward reaction

Addition of $$NaN{O_2}$$ favours reverse reaction

Increasing pressure favours reverse reaction

Increasing temperature favours forward reaction

## Questions 33 of 50

Question:For the reaction : $${H_{2(g)}} + C{O_{2(g)}}$$ $$\Leftrightarrow$$$$C{O_{(g)}} + {H_2}{O_{(g)}}$$, if the initial concentration of $$[{H_2}] = [C{O_2}]$$ and $$x$$ moles/litre of hydrogen is consumed at equilibrium, the correct expression of $${K_p}$$ is

$$\frac{{{x^2}}}{{{{(1 - x)}^2}}}$$

$$\frac{{{{(1 + x)}^2}}}{{{{(1 - x)}^2}}}$$

$$\frac{{{x^2}}}{{{{(2 + x)}^2}}}$$

$$\frac{{{x^2}}}{{1 - {x^2}}}$$

## Questions 34 of 50

Question:0.6 mole of NH3 in a reaction vessel of 2dm3 capacity was brought to equilibrium. The vessel was then found to contain 0.15 mole of H2 formed by the reaction$$2N{H_{3(g)}} = {N_{2(g)}} + 3{H_{2(g)}}$$Which of the following statements is true

0.15 mole of the original NH3 had dissociated at equilibrium

0.55 mole of ammonia is left in the vessel

At equilibrium the vessel contained 0.45 mole of $${N_2}$$

The concentration of NH$$^3$$ at equilibrium is 0.25 mole per dm$$^3$$

## Questions 35 of 50

Question:A reversible reaction is in equilibrium. If a factor is changed which affect it, then

The speed of forward and backward reaction increases

The speed of forward and backward reaction decreases

Only the speed of that reaction increases which nullifies the factor causing increase of speed

No difference

## Questions 36 of 50

Question:Which of the following reactions proceed at low pressure

$${N_2} + 3{H_2}$$ $$\Leftrightarrow$$ $$2N{H_3}$$

$${H_2} + {I_2}$$ $$\Leftrightarrow$$ $$2HI$$

$$PC{l_5}$$ $$\Leftrightarrow$$ $$PC{l_3} + C{l_2}$$

$${N_2} + {O_2}$$ $$\Leftrightarrow$$ $$2NO$$

## Questions 37 of 50

Question:Le-chatelier principle is applicable

Both for physical and chemical equilibrium

Only for chemical equilibrium

Only for physical equilibrium

Neither for (2) nor for (3c)

## Questions 38 of 50

Question:Consider the reaction $$HC{N_{(aq)}}$$ $$\Leftrightarrow$$ $$H_{(aq)}^ + + CN_{(aq)}^ -$$ . At equilibrium, the addition of $$CN_{(aq)}^ -$$ would

Reduce $$HC{N_{(aq)}}$$ concentration

Decrease the $$H_{(aq)}^ +$$ ion concentration

Increase the equilibrium constant

Decrease the equilibrium constant

## Questions 39 of 50

Question:In the gaseous equilibrium $${H_2}{X_2} +$$ heat $$\Leftrightarrow$$ $$2HX$$, the formation of $$HX$$ will be favoured by

High pressure and low temperature

High temperature and low pressure

Low temperature and low pressure

High temperature and high pressure

## Questions 40 of 50

Question:Raising the temperature of an equilibrium system

Favours the exothermic reaction only

Favours the endothermic reaction only

Favours both the exothermic and endothermic reactions

Favours neither the exothermic nor endothermic reactions

## Questions 41 of 50

Question:According to Le-chatelier's principle, which of the following factors influence a chemical system

Concentration only

Pressure only

Temperature only

Concentration, pressure and temperature

## Questions 42 of 50

Question:If pressure increases then its effect on given equilibrium $$C(s) + {H_2}O(g)$$ $$\Leftrightarrow$$$$CO(g) + {H_2}(g)$$ it is satisfied in

Forward direction

Backward direction

No effect

None of these

## Questions 43 of 50

Question:The exothermic formation of $$Cl{F_3}$$ is represented by the equation$$C{l_{2(g)}} + 3{F_{2(g)}}$$ $$\Leftrightarrow$$ $$2Cl{F_{3(g)}}$$; $$\Delta H = - 329\,kJ$$Which of the following will increase the quantity of $$Cl{F_3}$$ in an equilibrium mixture of $$C{l_2},\,{F_2}$$ and $$Cl{F_3}$$

Increasing the temperature

Removing $$C{l_2}$$

Increasing the volume of the container

Adding $${F_2}$$

## Questions 44 of 50

Question:Le-Chatelier’s principle is applicable only to a

System in equilibrium

Irreversible reaction

Homogeneous reaction

Heterogeneous reaction

## Questions 45 of 50

Question:In a vessel containing $$S{O_3},\,S{O_2}$$ and $${O_2}$$ at equilibrium, some helium gas is introduced so that the total pressure increases while temperature and volume remain constant. According to Le–Chatelier principle the dissociation of $$S{O_3}$$

Increases

Decreases

Remains unaltered

Changes unpredictably

## Questions 46 of 50

Question:$${H_{2(g)}} + {I_{2(g)}}$$ $$\Leftrightarrow$$$$2H{I_{(g)}}\,\,\,\Delta H = + q$$cal, then formation of HI:

Is favoured by lowering the temperature

Is favoured by increasing the pressure

Is unaffected by change in pressure

Is unaffected by change in temperature

## Questions 47 of 50

Question:The formation of nitric oxide by contact process $${N_2} + {O_2}$$ $$\Leftrightarrow$$ 2NO. $$\Delta$$H = 43.200 kcal is favoured by

Low temperature and low pressure

Low temperature and high pressure

High temperature and high pressure

High temperature and excess reactants concentration

## Questions 48 of 50

Question:The chemical reaction: $$Ba{O_{2(S)}}$$ $$\Leftrightarrow$$$$Ba{O_{(s)}}$$$$+ {O_{2(g)}}$$’ $$\Delta$$H = + ve. In equilibrium condition, pressure of O$$_{\rm{2}}$$ depends upon

Increase mass of BaO

Increase mass of BaO$$_{\rm{2}}$$

Increase in temperature

Increase mass of BaO$$_{\rm{2}}$$ and BaO both

## Questions 49 of 50

Question:The yield of product in the reaction $${A_{2(g)}}$$+ $$2{B_{\left( g \right)}}$$ $$\Leftrightarrow$$ $${C_{(g)}}$$+ Q.kJ. would be high at

High temperature and high pressure

High temperature and low pressure

Low temperature and high pressure

Low temperature and low pressure

## Questions 50 of 50

Question:Which reaction is not effected by change in pressure

$${H_2} + {I_2}$$ $$\Leftrightarrow$$$$2HI$$
$$2C + {O_2}$$ $$\Leftrightarrow$$ 2CO
$${N_2} + 3{H_2}$$ $$\Leftrightarrow$$$$2N{H_3}$$
$$PC{l_5}$$ $$\Leftrightarrow$$$$PC{l_3} + C{l_2}$$