Question

Vant' Hoff equation shows the effect of temperature on equilibrium constants $K_c$ and $K_p.$ The $K_p$ varies with temperature according to the relation:

• A. $log\frac{K_{p_2}}{K_{p_1}}=\frac{△H}{2.303R}\left[\frac{T_1-T_2}{T_1{T}_2}\right]$
• B. $log\frac{K_{p_2}}{K_{p_1}}=\frac{△H}{2.303R}\left[\frac{T_2-T_1}{T_1{T}_2}\right]$
• C. $log\frac{K_{p_2}}{K_{p_1}}=\frac{△H}{2.303R}\left[\frac{T_1{T}_2}{T_1-T_2}\right]$
• D. $log\frac{K_{p_2}}{K_{p_1}}=\frac{△H}{2.303R}\left[\frac{T_1{T}_2}{T_2-T_1}\right]$

Answer 1

The correct option is B $log\frac{K_{p_2}}{K_{p_1}}=\frac{△H}{2.303R}\left[\frac{T_2-T_1}{T_1{T}_2}\right]$

$K_p=A{e}^{-△H/RT}$
$log{K}_{eq.}=logA-\frac{△H^o}{2.303RT}$
On applying the limit of initial and final states, we will get the option (b).

$log\frac{K_{p_2}}{K_{p_1}}=\frac{△H}{2.303R}\left[\frac{T_2-T_1}{T_1{T}_2}\right]$