For a reversible reaction $A \rightleftharpoons B$,the half-life periods of the forward and backward reactions are $15 \ s$ and $18 \ s$,respectively. If both reactions follow first-order kinetics,what is the equilibrium constant $(K_c)$ of the reaction?

Some solid $NH_4HS$ is placed in a flask containing $0.5 \ atm$ of $NH_3$. What would be the partial pressures of $NH_3$ and $H_2S$ when equilibrium is reached for the reaction $NH_4HS_{(s)} \rightleftharpoons NH_{3_{(g)}} + H_2S_{(g)}$,given $K_p = 0.11$?

For the reaction $N_{2(g)} + 3H_{2(g)} \rightleftharpoons 2NH_{3(g)}$,the equilibrium constant $K_p = 41$ at $400 \ K$. Calculate $K_c$ for the following reactions at $400 \ K$:
$(a)$ $2N_{2(g)} + 6H_{2(g)} \rightleftharpoons 4NH_{3(g)}$
$(b)$ $2NH_{3(g)} \rightleftharpoons N_{2(g)} + 3H_{2(g)}$
$(c)$ $\frac{1}{2}N_{2(g)} + \frac{3}{2}H_{2(g)} \rightleftharpoons NH_{3(g)}$

At $800 \ K$ in a closed vessel,the molar concentrations of $N_2, O_2$ and $NO$ at equilibrium are $3.2 \times 10^{-3} \ M, 4.2 \times 10^{-3} \ M$ and $2.8 \times 10^{-3} \ M$ respectively. The approximate values of $K_{c}$ and $\frac{1}{K_{c}}$ for the following reaction are respectively: $N_{2(g)} + O_{2(g)} \rightleftharpoons 2 NO_{(g)}$

For the reaction $A_{(g)} + 2B_{(g)} \rightleftharpoons 2C_{(g)}$,$1 \ mol$ of $A$ and $1.5 \ mol$ of $B$ are taken in a $2 \ L$ vessel. If the concentration of $C$ at equilibrium is $0.35 \ M$,then the equilibrium constant $K_c$ of the reaction will be ....... $M^{-1}$.

The equilibrium constant for the reaction $N_{2(g)} + O_{2(g)} \rightleftharpoons 2NO_{(g)}$ at temperature $T$ is $4 \times 10^{-4}$. The value of $K_c$ for the reaction $NO_{(g)} \rightleftharpoons \frac{1}{2}N_{2(g)} + \frac{1}{2}O_{2(g)}$ at the same temperature is