Answer:
- 7.4 ÂșC
Explanation:
The change in melting  temperature is given by:
ÎTm = Kf m
where kf is the molal freezing  point depresion  constant, and m is the molality.
The molality of a solution is calculated as
m = mol solute/ kg solvent
Since we have the % composition it is easy to calculate the molality :
In 100 g of solution we have  24.9 ethylene glycol
mol glycol = 24.9 g / 62.07 g/ mol = 0.40 mol
molality = 0.40 mol / 0.1 kg = 4 m
Km for water is 1.86 ÂșC/m,
therefore, Â
ÎTm = Kf m = 1.86 ÂșC/m x 4 = 7.4 ÂșC
Tm = -7.4 ÂșC for a solution
