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Consider the following liquid-vapour equilibrium: Liquid $\rightleftharpoons$ Vapour. Which of the following relations is correct?
A
$\frac{d\ln P}{dT} = \frac{-\Delta H_v}{RT}$
B
$\frac{d\ln P}{dT^2} = \frac{-\Delta H_v}{T^2}$
C
$\frac{d\ln P}{dT} = \frac{\Delta H_v}{RT^2}$
D
$\frac{d\ln G}{dT^2} = \frac{-\Delta H_v}{RT^2}$
Explanation
Vapour pressure varies with T as ΔHv/RT².
Detailed Solution
The relation is the Clausius–Clapeyron equation: $\frac{d\ln P}{dT} = \frac{\Delta H_v}{RT^2}$