In which of the following reactions will an increase in pressure shift the equilibrium in the backward direction?

In the lime kiln,the reaction $CaCO_{3(s)} \to CaO_{(s)} + CO_{2(g)}$ goes to completion because

When $I_2$ dissociates to its atomic form the following reaction occurs:
$I_{2(g)} \rightleftharpoons 2I_{(g)} ; \Delta_r H^o = +150 \ kJ \ mol^{-1}$
The forward reaction is favoured at:

Consider the heterogeneous equilibrium in a closed container:
$NH_4HS_{(s)} \rightleftharpoons NH_{3(g)} + H_2S_{(g)}$
If more $NH_4HS_{(s)}$ is added to the equilibrium,what will be the effect on the system?

Aqueous solution of ferric nitrate when mixed with aqueous solution of potassium thiocyanate gives a red coloured solution. The intensity of the red colour becomes constant upon attaining equilibrium. Choose the correct statement when the following chemicals are added to the above solution at equilibrium:
$I$. Oxalic acid
$II$. Mercuric chloride

The formation of $SO_3$ takes place according to the following reaction: $2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)$; $\Delta H = -45.2 \ kcal$. The formation of $SO_3$ is favoured by: