The equilibrium constants for the following reactions are given at $25^{\circ} C$:
$2 A \rightleftharpoons B + C, K_{1} = 1.0$
$2 B \rightleftharpoons C + D, K_{2} = 16$
$2 C + D \rightleftharpoons 2 P, K_{3} = 25$
The equilibrium constant for the reaction $P \rightleftharpoons A + \frac{1}{2} B$ at $25^{\circ} C$ is

Give the equilibrium constant expression for the following reactions:
$(a)$ $Ni_{(s)} + 4CO_{(g)} \rightleftharpoons Ni(CO)_{4_{(g)}}$
$(b)$ $Ag_{2}O_{(s)} + 2HNO_{3_{(aq)}} \rightleftharpoons 2AgNO_{3_{(aq)}} + H_{2}O_{(l)}$

For the following three reactions $a, b$ and $c,$ equilibrium constants are given:
$(i)$ $CO_{(g)} + H_2O_{(g)} \rightleftharpoons CO_{2(g)} + H_{2(g)}$ ; $K_1$
$(ii)$ $CH_{4(g)} + H_2O_{(g)} \rightleftharpoons CO_{(g)} + 3H_{2(g)}$ ; $K_2$
$(iii)$ $CH_{4(g)} + 2H_2O_{(g)} \rightleftharpoons CO_{2(g)} + 4H_{2(g)}$ ; $K_3$
Which of the following relations is correct?

$4.5 \ mol$ each of hydrogen and iodine are heated in a $10 \ L$ closed vessel. At equilibrium,$3 \ mol$ of $HI$ is formed. The equilibrium constant for the reaction $H_2(g) + I_2(g) \rightleftharpoons 2HI(g)$ will be:

In the reaction $PCl_{5(g)} \rightleftharpoons PCl_{3(g)} + Cl_{2(g)}$,the equilibrium concentrations of $PCl_5$ and $PCl_3$ are $0.4 \ mol/L$ and $0.2 \ mol/L$ respectively. If the value of $K_c$ is $0.5$,what is the concentration of $Cl_2$ in $mol/L$?

For the equilibrium $N_2 + 3H_2 \rightleftharpoons 2NH_3$,$K_c$ at $1000 \ K$ is $2.37 \times 10^{-3}$. If at equilibrium $[N_2] = 2 \ M$ and $[H_2] = 3 \ M$,the concentration of $NH_3$ is: (in $M$)