Answer:
The molality of the solution is 1.10 m/kg
Explanation:
Colligative property: freezing point depression.
ΔT = Kf. m
ΔT = T°fussion pure solvent - T° fussion solution
Kf = depression constant for water
0°C - (-2.05°C) = 1.86 °C/m . m
2.05°C = 1.86°C/m . m
2.05°C / 1.86° m/°C = m → 1.10 m/kg