For the chemical reaction $3X_{(g)} + Y_{(g)} \to X_3Y_{(g)}$,the amount of $X_3Y$ at equilibrium is affected by

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?
$(a)$ $PCl_{5(g)} \rightleftharpoons PCl_{3(g)} + Cl_{2(g)}$
$(b)$ $CaO_{(s)} + CO_{2(g)} \rightleftharpoons CaCO_{3(s)}$
$(c)$ $3Fe_{(s)} + 4H_{2}O_{(g)} \rightleftharpoons Fe_{3}O_{4(s)} + 4H_{2(g)}$

Which of the following factors will favour the reverse reaction in a chemical equilibrium?

On addition of an inert gas at constant volume to the reaction $N_2 + 3H_2 \rightleftharpoons 2NH_3$ at equilibrium,

According to Le Chatelier's principle,an increase in the temperature of the following reaction will:
$N_2 + O_2 \rightleftharpoons 2NO - 43,200 \ kcal$

For the reaction $PCl_{3(g)} + Cl_{2(g)} \rightleftharpoons PCl_{5(g)}$,the position of equilibrium can be shifted to the right by