Question

The amount of ice that will separate out on cooling a solution containing $50g$ of ethylene glycol in $200g$ water to $-{9.3}^{\circ }C$ is: $(K_f^{\prime }=1.86Kmolalit{y}^{-1})$

• A. $38.71g$
• B. $38.71mg$
• C. $42g$
• D. $42mg$

Answer 1

The correct option is A $38.71g$

Molar mass of ethelene glycol $\left(m\right)=62g$
Depression in freezing pont is given by:
$\therefore \Delta T=\frac{1000\times K_f^{\prime }\times w}{W.m}$

$\Rightarrow 9.3=\frac{1000\times 1.86\times 50}{62\times W}$

$\therefore W=161.29$
Remaing water out of $200g$ will be seperated as ice.

$\therefore Iceseparated=200-161.29=38.71g$