Solid $NH_4HS$ is placed in a flask containing $NH_3$ gas at a certain temperature and a pressure of $0.50 \ atm$. The $NH_4HS$ decomposes to form $NH_3$ gas and $H_2S$ gas. When equilibrium is established in the flask,the total pressure increases to $0.84 \ atm$. What is the equilibrium constant $(K_p)$ for the decomposition of $NH_4HS$ at this temperature?

Given the following equilibria:
$N_2 + 3H_2 \rightleftharpoons 2NH_3 : K_1$
$N_2 + O_2 \rightleftharpoons 2NO : K_2$
$H_2 + 1/2O_2 \rightleftharpoons H_2O : K_3$
Then the equilibrium constant for the reaction $2NH_3 + 5/2O_2 \rightleftharpoons 2NO + 3H_2O$ in terms of $K_1, K_2,$ and $K_3$ will be:

Consider the following reversible first-order reaction of $X$ at an initial concentration $[X]_{0}$. The values of the rate constants are $K_{f} = 2 \ s^{-1}$ and $K_{b} = 1 \ s^{-1}$.
$X \underset{K_{b}}{\stackrel{K_{f}}{\rightleftharpoons}} Y$
Which of the following plots correctly represents the concentration of $X$ and $Y$ as a function of time?

Consider the following two equilibrium reactions:
$i$. $2NH_{3(g)} \rightleftharpoons N_{2(g)} + 3H_{2(g)}$
$ii$. $2ND_{3(g)} \rightleftharpoons N_{2(g)} + 3D_{2(g)}$
What is the difference in their equilibrium constants $(K_c)$?

$5 \, \text{moles}$ of $PCl_5$ are heated in a closed vessel of $5 \, \text{L}$ capacity. At equilibrium,$40\%$ of $PCl_5$ is found to be dissociated. What is the value of $K_c$ (in $, \text{M}$)?

At $473 \ K$, equilibrium constant $K_{c}$ for decomposition of phosphorus pentachloride, $PCl_{5}$, is $8.3 \times 10^{-3}$. If decomposition is depicted as,
$PCl_{5(g)} \rightleftharpoons PCl_{3(g)} + Cl_{2(g)}, \Delta_{r}H^{\Theta} = 124.0 \ kJ \ mol^{-1}$
$(a)$ Write an expression for $K_{c}$ for the reaction.
$(b)$ What is the value of $K_{c}$ for the reverse reaction at the same temperature?
$(c)$ What would be the effect on $K_{c}$ if $(i)$ more $PCl_{5}$ is added $(ii)$ pressure is increased $(iii)$ the temperature is increased?