1. The equilibrium constant for the reversible reaction
\[N_{2}+3H_{2}\rightleftharpoons2NH_{3} \] is K and for the reaction

\[1\diagup2 N_{2}+3\diagup2 H_{2}\rightleftharpoons NH_{3} \] , the equilibrium constant is K'.
K and K' will be related as

a) K = K'

b) \[K' =\sqrt{K}\]

c) \[K =\sqrt{K'}\]

d) K × K' = 1

Explanation: \[K' =\sqrt{K}\]

2. If \[K_{1} and K_{2}\] are respective equilibrium constants for the two reactions \[XeF_{6}\left(g\right)+H_{2}O\left(g\right)\rightleftharpoons XeOF_{4}\left(g\right)+2HF\left(g\right)\]

\[XeO_{4}\left(g\right)+XeF_{6}\left(g\right)\rightleftharpoons XeOF_{4}\left(g\right)+XeO_{3}F_{2}\left(g\right)\]

the equilibrium constant for the reaction

\[XeO_{4}\left(g\right)+2HF\left(g\right)\rightleftharpoons XeO_{3}F_{2}\left(g\right)+H_{2}O\left(g\right)\]

will be

a) \[\frac{K_{1}}{K_2^2}\]

b) \[K_{1}.K_{2}\]

c) \[\frac{K_{1}}{K_{2}}\]

d) \[\frac{K_{2}}{K_{1}}\]

Explanation: Reaction (II) and reverse of reaction (I) gives the desired reaction hence K = \[K_{2} \times \frac{1}{K_{1}} = \frac{K_{2}}{K_{1}}\]

3. A cylinder fitted with a movable piston contains liquid water in equilibrium with water vapour at 25°C. Which operation result in a decrease in the equilibrium vapour pressure

a) Moving the piston downward a short distance

b) Removing a small amount of vapour

c) Removing a small amount of the liquid water

d) Dissolving salt in the water

Explanation: Dissolution of salt lowers the V.P. It is also effected by temperature

4. The volume of the reaction vessel containing an equilibrium mixture in the reaction \[SO_{2}CI_{2}\left(g\right)\rightleftharpoons SO_{2}\left(g\right) + CI_{2}\left(g\right)\]

is increased when the equilibrium is re-established

a) The amount of \[SO_{2}\left(g\right)\] will decrease

b) The amount of \[SO_{2}CI_{2}\left(g\right)\] will increase

c) The amount of \[CI_{2}\left(g\right)\] will increase

d) The amount of \[CI_{2}\left(g\right)\] will remain unchanged

Explanation: It will decrease the concentration. The equilibrium will shift in the direction where more moles are formed to keep K

_{c}constant.

5. In gaseous equilibrium the correct relation between \[K_{C} and K_{P}\] is

a) \[K_{c}=K_{p}\left(RT\right)^{\triangle n}\]

b) \[K_{p}=K_{c}\left(RT\right)^{\triangle n}\]

c) \[\frac{K_{c}}{RT}=\left(K_{p}\right)^{\triangle n}\]

d) \[\frac{K_{p}}{RT}=\left(K_{c}\right)^{\triangle n}\]

Explanation: Relation is \[K_{p}=K_{c}\left(RT\right)^{\triangle n}\]

6. In which of the following reaction \[K_{P}>K_{C}\]

a) \[N_{2}+3H_{2}\rightleftharpoons 2NH_{3}\]

b) \[H_{2}+1_{2}\rightleftharpoons 2HI\]

c) \[PCl_{3}+Cl_{2}\rightleftharpoons PCl_{5}\]

d) \[2SO_{3}\rightleftharpoons O_{2}+2SO_{2}\]

Explanation: \[\triangle\]n = 3 – 2 = 1

\[K_{p}=K_{c}\left(RT\right)\] hence \[K_{P}>K_{C}\]

7. For reaction \[PCl_{3}\left(g\right)+CI_{2}\left(g\right)\rightleftharpoons PCl_{5}\left(g\right)\] , the value of \[K_{C}\] at 250°C is 26 mol^{–1} litre^{1}. The value of \[K_{P}\] at this
temperature will be

a) \[0.61 atm^{-1}\]

b) \[0.57 atm^{-1}\]

c) \[0.83 atm^{-1}\]

d) \[0.46 atm^{-1}\]

Explanation: \[\triangle\]n = –1

K

_{p}= 26 × (0.0821 × 523)

^{–1}= 0.61 atm

^{–1}

8. The equilibrium constant for the reaction, \[N_{2}\left(g\right)+O_{2}\left(g\right)\rightleftharpoons 2NO\left(g\right) is 4 ×10^{-4}\] at 2000 K.
In presence of a catalyst, equilibrium is attained ten times faster. Therefore, the equilibrium constant, in presence of the catalyst, at 2000 K is

a) \[40 × 10^{-4}\]

b) \[4 × 10^{-4}\]

c) \[4 × 10^{-3}\]

d) difficult to compute without more data

Explanation: K

_{c}is not influenced by presence of a catalyst

9. For a chemical reaction \[2A + B\rightleftharpoons C\] , the thermodynamic equilibrium constant \[K_{P}\] is

a) in \[atm^{-2}\]

b) in \[atm^{-3}\]

c) in \[atm^{-1}\]

d) dimensionless

Explanation: Unit of K

_{p}= \[\left(Atm\right)^{\triangle n}\] = (Atm)

^{–2}(\[\triangle n\] = moles of products – moles of reactants)

10. When two reactants, A and B are mixed to give products C and D, the reaction quotient Q, at the initial stage of the reaction

a) is zero

b) decreases with time

c) is independent of time

d) increases with time

Explanation: Q increases with the formation of products

Q = \[\frac{[Conc. of Products]}{[Conc. of Reactants]}\]