Answer:
Freezing point of solution is -4.39°C
Explanation:
Freezing point depression's formula:
ΔT = Kf . m . i
ΔT = Freezing point of pure solvent - Freezing point of solution
0°C - X = 1.86°C/m . m . 2
i = Van't Hoff factor, ions dissolved in solution
MgCl₂ → Mg²⁺ + 2Cl⁻ i = 3 → 1 mol of Mg and 2 mol of chloride
Let's think the molality (mol/kg)
First of all, let's convert the mass of solvent from g to kg
100 g / 1000 = 0.1 kg
Molality (mol/kg) = 0.118 mol / 0.1 kg = 1.18 m
0°C - X = 1.86°C/m . 1.18 m . 2
X = - 4.39°C
