Question

The unit of ebullioscopic constant is ______.

• A. $K \,kg\, mol^{-1}\,$ or $\, K \,(\text{molality})^{-1}$
• B. $mol\, kg\, K^{-1}\, $ or $\, K^{-1}\, (\text{molality})$
• C. $ kg \,mol^{-1} \, K^{-1} \,$ or $\, K^{-1}\, (\text{molality})^{-1}$
• D. $K \, mol\, kg^{-1} \,$ or $\, K\, \text{(molality)}$

Answer 1

Answer: (A)

As we know from elevation in boiling point that $U$

$\Delta T_b = K_b m$

Unit of $K_b = \frac{\text{Unit of } \Delta T_b}{\text{Unit of} \,m}$

$= \frac{K}{mol\,kg^{-1}} = K\,mol^{-1} kg$