The relation between equilibrium constant $K_p$ and $K_c$ is

If $0.5 \ mol$ of $H_2$ and $0.5 \ mol$ of $I_2$ are reacted in a $10 \ L$ vessel at $444 \ ^\circ C$,and the equilibrium constant $K_c$ at the same temperature is $49$,then the ratio of $[HI]$ to $[I_2]$ is .......

For which one of the following reactions is $K_p = K_c$?

One mole $H_2O_{(g)}$ and one mole $CO_{(g)}$ are taken in a $1 \ L$ flask and heated to $725 \ K$. At equilibrium,$40 \%$ (by mass) of water reacted with $CO_{(g)}$ as follows: $H_2O_{(g)} + CO_{(g)} \rightleftharpoons H_{2_{(g)}} + CO_{2_{(g)}}$. The value of $K_p$ is:

For the reaction $PCl_{3(g)} + Cl_{2(g)} \rightleftharpoons PCl_{5(g)}$ at $250 \ ^\circ C$,the value of $K_c$ is $26$. The value of $K_p$ at the same temperature will be:

$4.0 \, mol$ of argon and $5.0 \, mol$ of $PCl_5$ are introduced into an evacuated flask of $100 \, L$ capacity at $610 \, K$. The system is allowed to equilibrate. At equilibrium,the total pressure of the mixture was found to be $6.0 \, atm$. The $K_p$ for the reaction is ...... [Given: $R = 0.082 \, L \, atm \, K^{-1} \, mol^{-1}$]