For the reaction $2X_{(g)} + Y_{(g)} \rightleftharpoons 2Z_{(g)} + 80 \ kcal$,which conditions of temperature and pressure will yield more $Z$ at equilibrium?

The equilibrium constant $K$ and reaction quotient $Q$ are in the ratio $K : Q = 0.33 : 1$. This means that:

The reaction $SO_2 + Cl_2 \rightleftharpoons SO_2Cl_2$ is exothermic. If some $SO_2$ is added to the equilibrium mixture at constant volume,then ...........

When $NaNO_{3(s)}$ is heated in a closed vessel,$O_{2(g)}$ is released and $NaNO_{2(s)}$ remains. The equilibrium is: $NaNO_{3(s)} \rightleftharpoons NaNO_{2(s)} + 1/2 O_{2(g)}$. Which of the following is correct?

Which of the following reactions will be affected by increasing the pressure? Also,mention whether the change will cause the reaction to proceed in the forward or backward direction.
$(i)$ $CaCl_{2(s)} \rightleftharpoons CO_{(g)} + Cl_{2(g)}$
$(ii)$ $CH_{4(g)} + 2S_{2(g)} \rightleftharpoons CS_{2(g)} + 2H_{2}S_{(g)}$
$(iii)$ $CO_{2(g)} \rightleftharpoons C_{(s)} + 2CO_{(g)}$
$(iv)$ $2H_{2(g)} + CO_{(g)} \rightleftharpoons CH_{3}OH_{(g)}$
$(v)$ $CaCO_{3(s)} \rightleftharpoons CaO_{(s)} + CO_{2(g)}$
$(vi)$ $4NH_{3(g)} + 5O_{2(g)} \rightleftharpoons 4NO_{(g)} + 6H_{2}O_{(g)}$

The role of a catalyst in a reversible reaction is to