For the reaction $2HI \rightleftharpoons H_2 + I_2$,which of the following is true?

For the reaction $P + Q \rightleftharpoons R + C$,the equilibrium constant $K_c$ is $10^{-2}$ and the forward rate constant $K_f$ is $10^{-1}$. The rate constant for the backward reaction $(K_b)$ will be:

Find out the value of $K_{c}$ for each of the following equilibria from the value of $K_{p}$:
$(i)$ $2 NOCl_{(g)} \longleftrightarrow 2 NO_{(g)} + Cl_{2(g)}$; $K_{p} = 1.8 \times 10^{-2}$ at $500 \ K$
$(ii)$ $CaCO_{3(s)} \longleftrightarrow CaO_{(s)} + CO_{2(g)}$; $K_{p} = 167$ at $1073 \ K$

$40\%$ of $HI$ undergoes decomposition to $H_2$ and $I_2$ at $300 \ K$. $\Delta G^{\ominus}$ for this decomposition reaction at one atmosphere pressure is $... \ J \ mol^{-1}$. [nearest integer]
(Use $R = 8.31 \ J \ K^{-1} \ mol^{-1}$; $\log 2 = 0.3010$; $\ln 10 = 2.3$; $\log 3 = 0.477$)

At $1000 \ K$,a vessel contains $CO_2$ at a pressure of $0.5 \ atm$. Some $CO_2$ is converted into $CO$ by the addition of graphite. If the total pressure at equilibrium is $0.8 \ atm$,what is the value of $K_p$ in $atm$?

For the reaction $PCl_{5(g)} \rightleftharpoons PCl_{3(g)} + Cl_{2(g)}$,what is the relationship between $K_p$ and $K_c$?