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# The amount of ice that will separate on cooling a solution containing 50g of ethylene glycol in 200g water to –9.3$^{\large\circ}$C is : [$K_f = 1.86 K molality^{–1}$]

$W_2 = 50 g, W_1 = x, K_f = 1.86 K molality^{−1}$
$M_2$ (for solute $C_2H_6O_2$) = 24 + 6 + 32 = 62g $mol^{−1}$
Freezing point depression ($\Delta T_f) = 9.3 ^{\large\circ}C$ (or) 9.3 K
$\Delta T_f=K_fm=\large\frac{K_f\times W_2\times 1000}{W_1\times M_2}$
$9.3=\large\frac{1000\times 1.86\times 50}{62\times W_2}$
$W_1=161.29$