$2$ moles each of $A$ and $B$ were taken in a container and the following reaction takes place: $2 \ A_{(g)} + B_{(g)} \rightleftharpoons 2 \ C_{(g)} + D_{(g)}$. When the system attains equilibrium,which of the following is true?

The equilibrium composition for the reaction $PCl_3 + Cl_2 \rightleftharpoons PCl_5$ at $298 \, K$ is given below.
$[PCl_3]_{eq} = 0.2 \, mol \, L^{-1}$
$[Cl_2]_{eq} = 0.1 \, mol \, L^{-1}$
$[PCl_5]_{eq} = 0.40 \, mol \, L^{-1}$
If $0.2 \, mol$ of $Cl_2$ is added at the same temperature,the equilibrium concentration of $PCl_5$ is $.... \times 10^{-2} \, mol \, L^{-1}$. Given: $K_c$ for the reaction at $298 \, K$ is $20$.

Consider a reversible reaction $2A + B \rightleftharpoons 2C$ having equilibrium constant $K_c = 25$. If a reaction vessel contains $2 \ mol$ of $A$,$0.25 \ mol$ of $B$,and $0.5 \ mol$ of $C$ in a $100 \ L$ vessel,what will be the direction of the reaction?

Calculate the partial pressure of carbon monoxide from the following:
$CO_{2(g)} + C_{(s)} \rightleftharpoons 2CO_{(g)}$ ; $K_{p1} = 2$
$CaCO_{3(s)} \rightleftharpoons CaO_{(s)} + CO_{2(g)}$ ; $K_{p2} = 8 \times 10^{-2}$

State the important biological and environmental chemical equilibrium with examples.

If the pressure in a reaction vessel for the following reaction is increased by decreasing the volume,what will happen to the concentrations of $CO$ and $CO_2$ ?
$H_2O_{(g)} + CO_{(g)} \rightleftharpoons H_{2(g)} + CO_{2(g)} + \text{Heat}$