Question

Kf for water is 1.86 K kg mol–1. If your automobile radiator holds 1.0 kg of water, how may grams of ethylene glycol (C2H6O2) must you add to get the freezing point of the solution lowered to –2.8⁰C ?

• A. 72 g
• B. 93 g
• C. 39 g
• D. 27 g

Answer 1

Answer: (B)

93 g

Answer 2

$\Delta$Tf = i × kf × m

2.8 = 1 × 1.86 × $\frac{x}{62 \times 1}$

x = $\frac{2.8 \times 62}{1.86}$= 93 gm