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?
$2CO_{(g)} \rightleftharpoons O_{2(g)} + 2CO_{2(g)}$

The reaction $C_2H_{6(g)} \rightleftharpoons C_2H_{4(g)} + H_{2(g)}$ is at equilibrium in a closed vessel at $1000 \ K$. The enthalpy change $(\Delta H)$ for the reaction is $137.0 \ kJ \ mol^{-1}$. Which one of the following actions would shift the equilibrium to the right?

The equilibrium $SO_2Cl_{2(g)} \rightleftharpoons SO_{2(g)} + Cl_{2(g)}$ is attained at $25 ^\circ C$ in a closed container and an inert gas helium is introduced. Which of the following statements is correct?

In which of the following reactions at equilibrium,the position of the equilibrium shifts towards the products,if the total pressure is increased?
$(I)$ $X_{2(g)} + 3Y_{2(g)} \rightleftharpoons 2XY_{3(g)}$
$(II)$ $X_{2(g)} + Y_{2(g)} \rightleftharpoons 2XY_{(g)}$
$(III)$ $X_{2(g)} + Z_{2(g)} \rightleftharpoons 2XZ_{(g)}$
$(IV)$ $X_{2(g)} + Y_{4(g)} \rightleftharpoons 2XY_{2(g)}$

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

In which of the following equilibrium reactions does the equilibrium shift to the right when the total pressure is decreased?