# 75g of ethylene glycol is dissolved in 500g water. The solution is placed in a refrigerator maintained at a temperature of 263.7K. What amount of ice will separate out at this temperature. (Kf water = 1.86 K/m) 1) 300g 2) 200g 3) 178g 4) 258g

1) Depression in freezing point, ΔTf = Tf(freezing point of the pure solvent) - Tf (freesing point when non-volatile solute is dissolved in it) = 273 - 263.7 K = 9.3 K

2) Now, we have to calculate the weight of the solvent i.e. water, W, which is equal to

$W=\frac{{k}_{f}×w×1000}{m×\Delta {T}_{f}}$

where, w and m are the weight and molar mass of the solute i.e ethylene glycol. kf is given.

So,

Hence the amount of ice which will separate out from 500 g of water will be = 500 - 242 = 258 g.

Hence option 4 is correct.

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