The unit of the equilibrium constant for the reversible reaction $H_2 + I_2 \rightleftharpoons 2HI$ is:

At $400 \ K$ in a closed vessel,the reaction $H_{2(g)} + I_{2(g)} \rightleftharpoons 2HI_{(g)}$ takes place. At equilibrium,the concentration of $H_2$ is $0.6 \ mol \ L^{-1}$,the concentration of $I_2$ is $0.8 \ mol \ L^{-1}$,and the concentration of $HI$ is $0.14 \ mol \ L^{-1}$. Calculate the equilibrium constant $(K_c)$.

The equilibrium constants for the reactions $(i)$,$(ii)$,and $(iii)$ are $K_1$,$K_2$,and $K_3$ respectively. Which of the following is the correct relationship?
$(i)$ $N_2 + 2O_2 \rightleftharpoons 2NO_2$
$(ii)$ $2NO_2 \rightleftharpoons N_2 + 2O_2$
$(iii)$ $NO_2 \rightleftharpoons 1/2 N_2 + O_2$

At $298 \ K$,the $K_c$ of the reaction $Cu(s) + 2Ag^+(aq) \rightleftharpoons Cu^{2+}(aq) + 2Ag(s)$ is $3.0 \times 10^{14}$. In a reaction mixture at a certain temperature,$[Cu^{2+}] = 1.8 \times 10^{-2} \ M$ and $[Ag^+] = 3.0 \times 10^{-9} \ M$. Is this reaction in equilibrium? In which direction will the reaction proceed?

In which of the following reactions will the concentration of the product be greater than the concentration of the reactant at equilibrium? ($k$ = equilibrium constant)

For the reaction $N_2O_{4(g)} \rightleftharpoons 2NO_{2(g)}$,the concentrations of $N_2O_4$ and $NO_2$ at equilibrium are $4.8 \times 10^{-2} \, mol \, L^{-1}$ and $1.2 \times 10^{-2} \, mol \, L^{-1}$ respectively. Calculate the value of $K_c$.