Question 44 • Chemistry
The freezing-point depression is the difference between the pure solvent and solution freezing points: ΔTf = (−63.5°C) − (−70.55°C) = 7.05°C. Using ΔTf = Kf m, the molality is m = 7.05°C ÷ 4.07°C·kg/mol ≈ 1.73 mol/kg. Rounded to the nearest listed value, this is 1.7 m, choice A.
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