question_answer 11)

Calculate the mass of ascorbic acid (vitamin C, C6H8O6) to be dissolved in 75 g of acetic acid to lower its melting point by 1.5°C. Given Kf = 3.9 K kg mol–1.

Answer:

Lowering in melting point or freezing point (Tf) = 1.5°C = 1.5 K Mass of solvent (CH3COOH), w1 = 75 g Molar of mass of solute (C6H8O6), M2 = 72 + 8 + 96 = 176 g mol-1. Applying the formula, or   = 5.077g.