Chemistry-(general)

NEET Chemistry (general) MCQ Question

Type: MCQ-numerical-Hard-Class 12

A solution is prepared by dissolving 2 grams of a non-volatile solute in 40 grams of water, producing a depression in freezing point of 0.93 K. Given that the molal freezing point depression constant (Kf) for water is 1.86 K kg mol, calculate the molar mass of the solute.

A

39.9 g/mol

B

79.8 g/mol

C

159.6 g/mol

D

319.2 g/mol

Correct Answer

Option B

Detailed Explanation

Using the formula ΔTf = (Kf × w2 × 1000) / (w1 × M2) and substituting the given values: 0.93 = (1.86 × 2 × 1000) / (40 × M2), solve for M2 to find molar mass of solute as 79.8 g/mol.

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