Question

For the reaction, $H_2\left(g\right)+I_2\left(g\right)\iff 2HI\left(g\right)$ at 721 K, the value of equilibrium constant is 50. The value of $K_p$ under the same conditions will be:

• A. 0.02
• B. 0.2
• C. 50
• D. (50/RT)

Answer 1

The correct option is C 50

The relationship between $K_p$ and $K_c$ is $K_p=K_c(RT{)}^{\Delta n}$.

When $\Delta n=0$, the term $(RT{)}^{\Delta n}$ becomes $(RT{)}^0=1$

Hence, $K_p=K_c$.

This is true for the reaction, $H_2\left(g\right)+I_2\left(g\right)\iff 2HI\left(g\right)$ for which $\Delta n=2-(1+1)=0$.

Hence, $K_p=K_c=50$.