Which of the following aqueous solution will exhibit highest boiling point?

Question

Professor PC Thomas Classes · Answer

(a) : Elevation in boiling point, $\Delta T_b=m 	imes i 	imes K_b$
or $\quad \Delta T_b \propto m 	imes i$
(As, $K_b$ is constant)
or $\quad \Delta T_b \propto$ concentration × no. of ions.
For $0.01 \mathrm{M} \mathrm{Na}_2 \mathrm{SO}_4, \Delta T_b=0.01 	imes 3 K_b=0.03 K_b$
For $0.015 \mathrm{M} \mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6, \Delta T_b=0.015 	imes 1 	imes K_b=0.015 K_b$
For 0.01 M urea, $\Delta T_b=0.01 	imes 1 	imes K_b=0.01 K_b$
For $0.01 \mathrm{M} \mathrm{KNO}_3, \Delta T_b=0.01 	imes 2 K_b=0.02 K_b$
Thus, $0.01 \mathrm{M} \mathrm{Na}_2 \mathrm{SO}_4$ solution will exhibit highest boiling point.