In a chemical reaction $A + 2B \rightleftharpoons 2C + D$,the initial concentration of $B$ was $1.5$ times of $A$ but the equilibrium concentrations of $A$ and $B$ were found to be equal. The equilibrium constant $(K)$ for the aforesaid chemical reaction is

In an alkaline medium,the sulfide ion reacts with solid sulfur to form polysulfide ions. The equilibrium constants for the formation of $S_2^{2-}$ and $S_3^{2-}$ from $S$ and $S^{2-}$ ions are $1.7$ and $5.3$,respectively. The equilibrium constant for the formation of $S_3^{2-}$ from $S_2^{2-}$ and $S$ will be .........

Two equilibria,$AB \rightleftharpoons A^{+} + B^{-}$ and $AB + B^{-} \rightleftharpoons AB_2^-$,are simultaneously maintained in a solution with equilibrium constants $K_1$ and $K_2$ respectively. The ratio of $[A^{+}]$ to $[AB_2^-]$ in the solution is

For the reaction $N_2 + O_2 \rightleftharpoons 2NO$,the equilibrium concentrations of $N_2$,$O_2$,and $NO$ are $0.25 \ mol/L$,$0.05 \ mol/L$,and $1.0 \ mol/L$ respectively. What are the initial concentrations of $N_2$ and $O_2$?

When $20 \ g$ of $CaCO_3$ are subjected to decomposition at $227 \ ^oC$ in a closed container of $10 \ L$ capacity,$50 \%$ of $CaCO_3$ remained unreacted at equilibrium. Calculate $K_P$ for $CaCO_{3(s)} \rightleftharpoons CaO_{(s)} + CO_{2(g)}$ in $atm$.

For the reaction,$0.5 C_{(s)} + 0.5 CO_{2(g)} \rightleftharpoons CO_{(g)}$,the equilibrium pressure is $12 \ atm$. If $CO_2$ conversion is $50 \%$,the value of $K_p$,in $atm$,is: