Question

For the reaction ;$2N{O}_2\left(g\right)\rightleftharpoons 2NO\left(g\right)+O_2\left(g\right)$, $K_c=1.8\times {10}^{-6}$ at ${184}^{\circ }$ C and R=0.083 $J{K}^{-1}mo{l}^{-1}$, when $K_p$ and $K_c$ are compared at ${184}^{\circ }$C, it is found that :

• A. $K_p>K_c$
• B. $K_p$ < $K_c$
• C. $K_p=K_c$
• D. $K_p\ge K_c$ depends upon pressure of gases

Answer 1

The correct option is A $K_p>K_c$

The relationship between $K_p$ and $K_c$ is $K_p=K_c(RT{)}^{\Delta n}$
When the value of $\Delta n$ is 1, the term $(RT{)}^{\Delta n}$ becomes more than 1.
In such case, $K_p>K_c$.
This is true for the reaction $2N{O}_2\left(g\right)\rightleftharpoons 2NO\left(g\right)+O_2\left(g\right)$ as $\Delta n=2+1-2=1$.