Question

The vapour pressure of water at ${27}^{o}C$ is $0.2463atm$. Calculate the values of $K_p$ and $K_c$ at ${27}^{o}C$ for the equilibrium $H_{2}O(l\rightleftharpoons H_{2}O(g)$
Using the equilibrium constant
Which of the following reactions goes almost all the way to completion, and which proceeds hardly.

Answer 1

$H_{2}O\left(l\right)\rightleftharpoons H_{2}O\left(g\right)T={27}^{0}C$

Vapour pressure $=P^{H_{2}O}=0.2463$

$K_P=P^{H_{2}O}=0.2463$

$K_P=K_C{\left(RT\right)}^{\Delta n}$

Here $\Delta n=1-0=1$

$K_C=\frac{K_P}{RT}=\frac{0.2463}{0.0821\times 300}=0.01$

Here $K\alpha 1$ So $K_b>K_f(\because K_f/K_b=K)$

backward reaction goes to completion, forward is hard.