Question
2 g nonelectrolyte solute when dissolved in 50 g water increases its boiling point by 0.13 K. Calculate the molar mass of solute if molal elevation constant of water is 0.52 K kg mol^ -1
MHT CET
Chemistry
Solutions
2026
MHT CET 2026 (13 April Shift 1)
MHT CET Chemistry Question (2026) — Solution
Options
- A. 140 g/mol
- B. 150 g/mol
- C. 160 g/mol
- D. 170 g/mol
Answer
C. 160 g/mol
Step-by-step solution
The elevation in boiling point is given by the formula: T_b = K_b m where m is the molality of the solution, which can be expressed as: m = w_2 1000 M_2 w_1 Substituting the expression for molality into the boiling point elevation formula gives: T_b = K_b w_2 1000 M_2 w_1 Rearranging to solve for the molar mass of the solute, M_2: M_2 = K_b w_2 1000 T_b w_1 Substituting the given values (K_b = 0.52 K kg mol^ -1 , w_2 = 2 g, T_b = 0.13 K, w_1 = 50 g): M_2 = 0.52 2 1000 0.13 50 M_2 = 4 40 = 160 g/mol
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