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, ΔT_f = T_f^o (freezing point of the pure solvent) - T_f (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

$W=\frac{k_f\times w\times 1000}{m\times \Delta T_f}$

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

So, $W=\frac{1.86 \times 75\times 1000}{62\times 9.3}=242 g$

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.