2 molal solution of a weak acid HA has a freezing point of 3.885°C. The degree of dissociation of this acid is _____ × 10?³. (Round off to the nearest integer).
[ Given : Molal depression constant of water = 1.85 K kg mol?¹, Freezing point of pure water = 0°C]
2 molal solution of a weak acid HA has a freezing point of 3.885°C. The degree of dissociation of this acid is _____ × 10?³. (Round off to the nearest integer).
[ Given : Molal depression constant of water = 1.85 K kg mol?¹, Freezing point of pure water = 0°C]
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1 Answer
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Given K_f = 1.85 K kg mol? ¹ for a solution with molality of 2 m.
ΔT_f = I * K_f * m
3.885 = I * 1.85 * 2
The van't Hoff factor, I = 1.05.
i = 1 + (n-1)α. For an electrolyte dissociating into 2 ions, n=2.
1.05 = 1 + (2-1)α.
The degree of dissociation, α = 0.05 or 50 × 10? ³.
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