Water has a Kf of 1.86 °C/m. Calculate the new freezing point of an aqueous solution made by mixing 34.12 g water and 1.700 g MgCl2.

The new freezing point is 0.98°C

Explanation:

T = m × Kf

m (molality of the aqueous solution) = number of moles of MgCl2/mass of water in kilogram

Number of moles of MgCl2 = 1.7/95 = 0.018 mol

Mass of water = 34.12 g = 34.12/1000 = 0.03412 kg

m = 0.018/0.03412 = 0.528 mol/kg

Kf = 1.86°C/m

T = 0.528 × 1.86 = 0.98°C