Question

The values of $K_b$ and $K_f$ for solvents obeying Trouton's rule are directly proportional to :

• A. $\frac{RT}{M}$
• B. $MT$
• C. $MRT$
• D. $M{T}^2$

Answer 1

The correct option is B $MT$

The values of $K_b$ and $K_f$ for solvents obeying Trouton's rule are directly proportional to $MT$.
Trouton's rule states that molar entropy of vaporization is constant. The enthalpy of vaporisation of many liquids may be estimated using Trouton's rule.
$\frac{\Delta H}{T}=constant$ (Trouton's rule)
$\therefore K_b=\frac{R{T}^{2}M}{\Delta H}\propto MT$