For the reaction $XCO_{3(s)} \rightleftharpoons XO_{(s)} + CO_{2(g)},$ $K_p = 1.642 \text{ atm}$ at $727^{\circ}C.$ If $4 \text{ moles}$ of $XCO_{3(s)}$ were placed into a $50 \text{ L}$ container and heated to $727^{\circ}C,$ what mole percent of the $XCO_3$ remains unreacted at equilibrium?

$PCl_{5} \rightleftharpoons PCl_{3} + Cl_{2} \quad K_{c} = 1.844$
$3.0 \ \text{moles}$ of $PCl_{5}$ is introduced in a $1 \ \text{L}$ closed reaction vessel at $380 \ \text{K}$. The number of moles of $PCl_{5}$ at equilibrium is $..... \times 10^{-3}$. (Round off to the Nearest Integer)

For the following reactions,equilibrium constants are given:
$S_{(s)} + O_{2(g)} \rightleftharpoons SO_{2(g)}; K_1 = 10^{52}$
$2S_{(s)} + 3O_{2(g)} \rightleftharpoons 2SO_{3(g)}; K_2 = 10^{129}$
The equilibrium constant for the reaction $2SO_{2(g)} + O_{2(g)} \rightleftharpoons 2SO_{3(g)}$ is:

$A$ $20 \, L$ container at $400 \, K$ contains $CO_{2(g)}$ at a pressure of $0.4 \, atm$ and an excess of $SrO$ (neglect the volume of solid $SrO$). The volume of the container is now decreased by moving the movable piston fitted in the container. The maximum volume of the container,when the pressure of $CO_2$ attains its maximum value,will be........$L$
(Given: $SrCO_{3(s)} \rightleftharpoons SrO_{(s)} + CO_{2(g)}, K_p = 1.6 \, atm$)

Air containing $79\%$ of nitrogen and $21\%$ of oxygen by volume is heated at $2200 \ K$ and $1 \ atm$ until equilibrium is established according to the reaction $N_{2(g)} + O_{2(g)} \rightleftharpoons 2NO_{(g)}$. If the $K_p$ of the reaction is $1.1 \times 10^{-3}$,calculate the amount of nitric oxide produced in terms of volume percent.

For a reaction taking place in a container in equilibrium with its surroundings,the effect of temperature on its equilibrium constant $K$ in terms of change in entropy is described by: