What happens when an inert gas is added to an equilibrium system while keeping the volume unchanged?

In the reaction $A_{(g)} + B_{(g)} \rightleftharpoons C_{(g)}$,the backward reaction is favoured by

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:

Mention the conditions required to maximize the yield of ammonia.

According to Le $Chatelier$ principle,if heat is given to a solid-liquid system,then:

The endothermic reaction $(M + N \rightleftharpoons P)$ is allowed to attain an equilibrium at $25^o C$. Formation of $P$ can be increased by