$4.5$ moles each of hydrogen and iodine are heated in a sealed $10 \ L$ vessel. At equilibrium,$3$ moles of $HI$ are found. The equilibrium constant for ${H_2}_{(g)} + {I_2}_{(g)} \rightleftharpoons 2HI_{(g)}$ is

For the reaction $N_2O_{4(g)} \rightleftharpoons 2NO_{2(g)}$,the concentrations of $N_2O_4$ and $NO_2$ at equilibrium are $4.8 \times 10^{-2} \, mol \, L^{-1}$ and $1.2 \times 10^{-2} \, mol \, L^{-1}$ respectively. Calculate the value of $K_c$.

$4$ moles of $A$ are mixed with $4$ moles of $B$. At equilibrium for the reaction $A + B \rightleftharpoons C + D$,$2$ moles of $C$ and $D$ are formed. The equilibrium constant for the reaction will be

For the reaction $H_{2(g)} + I_{2(g)} \rightleftharpoons 2HI_{(g)}$,the value of $K_p$ changes with:

Before any reaction takes place,the value of the reaction quotient $(Q_c)$ is ......

For the chemical equilibrium $A + B \rightleftharpoons C + D$,when one mole of each reactant is mixed,$0.4 \ mol$ of each product is formed. The equilibrium constant $K_c$ is: