STANDARDChemistry-Solutions

STANDARD Chemistry Colligative Properties MCQ Question

Type: MCQ-numerical-Medium-Class 12

The elevation in boiling point of a solution of 9.43 g of MgCl₂ in 1 kg of water is (K_b = 0.52 K kg mol⁻¹, Molar mass of MgCl₂ = 94.3 g mol⁻¹)

A

0.156

B

0.52

C

0.17

D

0.94

Correct Answer

Option A

Detailed Explanation

MgCl₂ dissociates into Mg²⁺ and 2Cl⁻ ions, giving i = 3. The elevation in boiling point (ΔT_b) is calculated using ΔT_b = iK_bm, where m is the molality. Substituting the values, ΔT_b = 3 × 0.52 × (9.43 / 94.3) = 0.156 K.

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