Which of the following reactions will get affected by increasing the pressure? Also, mention whether the change will cause the reaction to go in a forward or backward direction?

${\mathrm{CaCO}}_3 \left(\mathrm{s}\right)\rightleftharpoons \mathrm{CaO} \left(\mathrm{s}\right)+{\mathrm{CO}}_2 \left(\mathrm{g}\right)$

State how the following reaction will be affected by increasing the pressure. Also mention whether the change will cause the reaction to go in a forward or backward direction.

The following two equilibria exist simultaneously in a closed vessel:
${\mathrm{PCl}}_5 \left(\mathrm{g}\right)\rightleftharpoons {\mathrm{PCl}}_3 \left(\mathrm{g}\right)+{\mathrm{Cl}}_2 \left(\mathrm{g}\right)$
${\mathrm{COCl}}_2 \left(\mathrm{g}\right)\rightleftharpoons \mathrm{CO} \left(\mathrm{g}\right)+{\mathrm{Cl}}_2 \left(\mathrm{g}\right)$

If some $\mathrm{CO}$ is added into the vessel, then after the equilibrium is attained again, concentration of

When hydrochloric acid is added to cobalt nitrate solution at room temperature, the following reaction takes place and the reaction mixture becomes blue. On cooling the mixture, it becomes pink. On the basis of this information, mark the correct answer.

$$\begin{gathered} {\left[\mathrm{Co}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{3+}\left(\mathrm{aq}\right)+4{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)\rightleftharpoons {\left[\mathrm{Co}(\mathrm{Cl}{)}_4\right]}^{2-}\left(\mathrm{aq}\right)+6{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \\ { }^{\left(\mathrm{pink}\right)} { }^{ \left(\mathrm{Blue}\right)} \end{gathered}$$
 

On increasing the pressure, in which direction will the gas phase reaction proceed to re-establish, (as predicted by applying the Le Chatelier's principle) for the reaction: ${\mathrm{N}}_2 \left(\mathrm{g}\right)+3{\mathrm{H}}_2 \left(\mathrm{g}\right)\rightleftharpoons 2{\mathrm{NH}}_3 \left(\mathrm{g}\right)$. Which of the following options is correct, if the total pressure at which the equilibrium is established, is increased without changing the temperature?