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?

$4.0 \, mol$ of argon and $5.0 \, mol$ of $PCl_5$ are introduced into an evacuated flask of $100 \, L$ capacity at $610 \, K$. The system is allowed to equilibrate. At equilibrium,the total pressure of the mixture was found to be $6.0 \, atm$. The $K_p$ for the reaction is ...... [Given: $R = 0.082 \, L \, atm \, K^{-1} \, mol^{-1}$]

For the reaction: $NH_4HS_{(s)} \rightleftharpoons NH_{3(g)} + H_2S_{(g)}$,the observed pressure of reaction mixture at equilibrium is $1.4 \ atm$ at $110 \ ^oC$. Value of $K_p$ for the reaction is ..... $atm^2$

For the reaction,$PCl_{3(g)} + Cl_{2(g)} \rightleftharpoons PCl_{5(g)}$,the value of $K_c$ at $250 \ ^oC$ is $26$. The value of $K_p$ at this temperature will be:

At $600\ ^{\circ}C$,$NH_4COONH_2\ (s) \rightleftharpoons 2NH_3\ (g) + CO_2\ (g)$ has an equilibrium constant $K_p = 3.2 \times 10^2\ bar^3$. Calculate $K_c$. $\left( R = 0.082\ L\ atm\ K^{-1}\ mol^{-1} \right)$

$A_{(s)} \rightleftharpoons M_{(s)} + \frac{1}{2} O_{2(g)}$
The equilibrium constant for the reaction is $K_{p} = 4$. At equilibrium,the partial pressure of $O_{2}$ is $.... \ atm.$ (Round off to the nearest integer).