Chemical and Ionic Equilibrium 1 Question 3
3. For the reaction,
$2 \mathrm{SO}{2}(g)+\mathrm{O}{2}(g) \longrightarrow 2 \mathrm{SO}{3}(g), \Delta H=-57.2 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $K{c}=1.7 \times 10^{16}$. Which of the following statement is incorrect?
(2019 Main, 10 April II)
(a) The equilibrium constant decreases as the temperature increases
(b) The addition of inert gas at constant volume will not affect the equilibrium constant
(c) The equilibrium will shift in forward direction as the pressure increases
(d) The equilibrium constant is large suggestive of reaction going to completion and so no catalyst is required
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Solution:
- The explanation of given statements are as follows:
(a) For the given equilibrium, $\Delta H$ is negative, so the equilibrium constant will decrease with increase in temperature and the equilibrium will shift in the backward direction.
Thus, statement (a) is correct.
(b) When inert gas is added at constant volume and constant temperature, an equilibrium remains undisturbed.
Thus, statement (b) is correct. (c) For the equilibrium,
$$ \Delta n_{g}=2-(2+1)=-1 \text {, i.e. }(-\mathrm{ve}) $$
So, increase in pressure will shift the equilibrium in the forward direction.
Thus, statement (c) is correct.
(d) The reaction takes place in the presence of a catalyst which is $\mathrm{V}{2} \mathrm{O}{5}(s)$ in contact process or $\mathrm{NO}(g)$ in chamber process.
Thus, statement (d) is incorrect.
