For the reaction $P_{4(s)} + 5O_{2(g)} \rightleftharpoons P_4O_{10(s)}$,the equilibrium constant expression $K_c$ is:

Which of the following statements is true when equilibrium is established in the reaction? $A + B \rightleftharpoons C + D, K_C = 10$

$K_{a_1}, K_{a_2}$ and $K_{a_3}$ are the respective ionization constants for the following reactions $(a), (b),$ and $(c)$.
$(a)$ $H_2C_2O_4 \rightleftharpoons H^{+} + HC_2O_4^-$
$(b)$ $HC_2O_4^- \rightleftharpoons H^{+} + C_2O_4^{2-}$
$(c)$ $H_2C_2O_4 \rightleftharpoons 2H^{+} + C_2O_4^{2-}$
The relationship between $K_{a_1}, K_{a_2}$ and $K_{a_3}$ is given as

At $298 \ K$,for the reaction $Ag^{+} + 2NH_3 \rightleftharpoons Ag(NH_3)_2^{+}$,the concentrations of $Ag^{+}$,$Ag(NH_3)_2^{+}$,and $NH_3$ are $10^{-1} \ M$,$10^{-1} \ M$,and $10^3 \ M$ respectively. The value of $K_c$ at $298 \ K$ for this equilibrium is ...... .

For the reaction $2H_2S_{(g)} \rightleftharpoons 2H_{2(g)} + S_{2(g)}$,the equilibrium mixture is given. If $1 \ mol$ of $H_2S$,$0.2 \ mol$ of $H_2$,and $0.8 \ mol$ of $S_2$ are taken in a $2 \ L$ vessel,find the value of $K_c$.

At $298 \ K$,the $K_c$ of the reaction $Cu(s) + 2Ag^+(aq) \rightleftharpoons Cu^{2+}(aq) + 2Ag(s)$ is $3.0 \times 10^{14}$. In a reaction mixture at a certain temperature,$[Cu^{2+}] = 1.8 \times 10^{-2} \ M$ and $[Ag^+] = 3.0 \times 10^{-9} \ M$. Is this reaction in equilibrium? In which direction will the reaction proceed?