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. Kf = 3.9 K kg mol−1.

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. Kf = 3.9 K kg mol⁻¹.

Solution

Given that

Mass of acetic acid, w1 = 75 g

Molar mass of ascorbic acid (C₆H₈O₆), M₂ = 6 × 12 + 8 × 1 + 6 × 16 = 176 g mol₋₁

Lowering of melting point, ∆T_f = 1.5 K

Use same formula again we get

 

w₂= 5.08 g

Answer 

Required mass o ascorbic acid =5.08 g