A solution containing 62 ethylene glycol in 250 g water is cooled to -10℃. If Kf for water is 1.86 K kg mol-1, the amount of water (in g) separated as ice is:

Calculation:Considering the expression of the depression in freezing point of the solution,∆Tf = Kf × m × i\(T_f^\circ - {T_f} = {K_f} \times {\rm{\;}}\frac{{{w_B} \times 1000}}{{{M_B} \times {w_A}\left( {in\;G} \right)}} \times {\rm{\;}}i\) ----(1)Here, \(T_f^\circ = 0 ^\circ C,\;{T_f} = - 10\)wB = mass of ethylene glycol = 62 gMB is molar mass of ethylene glycol = 62 g mol-1wA= mass of water in gas LIQUID SOLVENT,I = van’t Hoff FACTOR = 1(for ethylene glycol in water)Kf = 1.86 K kg mol-1On substituting in equation (1), we get\(0 - \left( { - 10} \right) = 186 \times \frac{{62 \times 1000}}{{62 \times {w_A}}} \times 1\)\({w_A} = \frac{{186 \times 62 \times 1000}}{{10 \times 62}} = 186\;g\)So, the amount of water separated as ice (solid solvent) = 250 – wA= (250 – 186) g = 64 g.