Ethylene glycol is used as an antifreeze in a cold climate. What is the mass of ethylene glycol which should be added to 4 kg of water to prevent it from freezing at -6oC? (Kf for water = 1.86 K kg/mol and molar mass of ethylene glycol = 62 g/mol)
Answer & explanation
Correct answer: option 3
Depression in freezing point, ΔTf = \(\frac{Kf × 1000 × W_2}{W_1 × M_2}\)
6 = \(\frac{1.86 × 1000 × W_2}{4000 × 62}\)
W2 = \(\frac{6 × 4000 × 62}{1.86 × 1000}\) = 800 g