Before any reaction takes place,the value of the reaction quotient $(Q_c)$ is ......

The equilibrium constant expression for the reaction $P_{4(s)} + 5O_{2(g)} \rightleftharpoons P_4O_{10(s)}$ is:

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?
$(i)$ $N_2 + 2O_2 \rightleftharpoons 2NO_2$
$(ii)$ $2NO_2 \rightleftharpoons N_2 + 2O_2$
$(iii)$ $NO_2 \rightleftharpoons 1/2 N_2 + O_2$

The figure shows the change in concentration of species $A$ and $B$ as a function of time. The equilibrium constant $K_C$ for the reaction $2A_{(g)} \rightleftharpoons B_{(g)}$ is

The equilibrium constant for the reaction $SO_{2(g)} + \frac{1}{2} O_{2(g)} \rightleftharpoons SO_{3(g)}$ is $5 \times 10^{-2} \ atm^{-1/2}$. The equilibrium constant of the reaction $2 SO_{3(g)} \rightleftharpoons 2 SO_{2(g)} + O_{2(g)}$ would be

$2 NOCl_{(g)} \rightleftharpoons 2 NO_{(g)} + Cl_{2(g)}$
In an experiment,$2.0 \ mol$ of $NOCl$ was placed in a $1 \ L$ flask and the concentration of $NO$ after equilibrium was established,was found to be $0.4 \ mol/L$. The equilibrium constant at $30^{\circ} C$ is $....... \times 10^{-4}$.