Question

Ishan’s automobile radiator is filled with 1.0 kg of water. How many grams of ethylene glycol (Molar mass = 62 g mol^–1 ) must Ishan add to get the freezing point of the solution lowered to –2.8 ºC. K_f for water is 1.86 K kg mol^–1 .

Answer 1

\(\Delta \text{T}_f = \text{K}_f \ m\)

Let x g of ethylene glycol is added to radiator

\(\Rightarrow \Delta \text{T}_f = \text{K}_f\frac{\text{x}}{62 \times 1}\)

\(\text{x} = \frac{62\Delta \text{T}_f}{\text{K}_f} = \frac{62 \times 2.8}{1.86}\)

\(\Rightarrow \text{x} = 93.33\)