JEE PYQ: Solutions And Colligative Properties Question 5
Question 5 - 2021 (18 Mar Shift 1)
2 molal solution of a weak acid HA has a freezing point of $3.885°C$. The degree of dissociation of this acid is ____ $\times 10^{-3}$.
[Given: $K_f = 1.85$ K kg mol$^{-1}$, Freezing point of pure water $= 0°C$]
Show Answer
Answer: 50
Solution
$\Delta T_f = (1 + \alpha)K_f m$. $\alpha = 0.05 = 50 \times 10^{-3}$.