In which of the following equilibrium reactions,the equilibrium would shift to the right,if total pressure is increased?

Does the number of moles of reaction products increase,decrease,or remain the same when each of the following equilibria is subjected to a decrease in pressure by increasing the volume?
$(a)$ $PCl_{5(g)} \rightleftharpoons PCl_{3(g)} + Cl_{2(g)}$
$(b)$ $CaO_{(s)} + CO_{2(g)} \rightleftharpoons CaCO_{3(s)}$
$(c)$ $3Fe_{(s)} + 4H_{2}O_{(g)} \rightleftharpoons Fe_{3}O_{4(s)} + 4H_{2(g)}$

Sodium sulphate dissolves in water with the evolution of heat. Consider a saturated solution of sodium sulphate. If the temperature is raised,then according to Le Chatelier's principle:

Describe the effect of:
$(a)$ Addition of $H_2$
$(b)$ Addition of $CH_3OH$
$(c)$ Removal of $CO$
$(d)$ Removal of $CH_3OH$ on the equilibrium of the reaction:
$2H_{2(g)} + CO_{(g)} \longleftrightarrow CH_3OH_{(g)}$

For the following balanced reaction occurring at a constant temperature,what will be the change in the concentration of $CO$ if the volume of the system is decreased?
$2CO_{(g)} \rightleftharpoons O_{2(g)} + 2CO_{2(g)}$

In the following reversible reaction $2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g) + Q \ \text{cal}$. The most suitable condition for the higher production of $SO_3$ is: