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 $K_c$ is 50. When the equilibrium concentration of both is 0.5 M, value of $K_p$ under the same conditions will be:

• A. 0.002
• B. 0.2
• C. 50
• D. 50/RT

Answer 1

The correct option is C 50

The equilibrium reaction is $H_2\left(g\right)+I_2\left(g\right)\iff 2HI\left(g\right)$.
The relationship between $K_p$ and $K_c$ is $K_p=K_c(RT{)}^{\Delta n}$.
For the equilibrium reaction, $\Delta n=2-(1+1)=0$.
Hence, $K_p=K_c=50$.