Which of the following equilibria is not affected by a change in the volume of the flask?

Two systems $PCl_{5(g)} \rightleftharpoons PCl_{3(g)} + Cl_{2(g)}$ and $COCl_{2(g)} \rightleftharpoons CO_{(g)} + Cl_{2(g)}$ are in equilibrium simultaneously in a container of constant volume. If some $CO_{(g)}$ is added to the container at constant volume,then at the new equilibrium:

For the reaction $Cl_{2(g)} + 3F_{2(g)} \rightleftharpoons 2ClF_{3(g)}; \Delta H = -329 \, kJ$,which of the following will increase the amount of $ClF_{3(g)}$ in the equilibrium mixture?

When a vapor is heated slowly from $25\,^oC$ at atmospheric pressure,its color initially deepens. When the temperature is increased above $160\,^oC$,the color fades. At $600\,^oC$,the vapor becomes almost colorless,but when the pressure is increased at this temperature,the color deepens again. What is this vapor?

For the chemical reaction: $BaO_{2(s)} \rightleftharpoons BaO_{(s)} + \frac{1}{2} O_{2(g)}$,$\Delta H = +ve$. At equilibrium,the pressure of $O_2$ depends upon:

In a reversible reaction,a catalyst is a substance that .....