Question

The freezing point of a solution containing $50{\text{cm}}^3$ of ethylene glycol in $50\text{g}$ of water is found to be $-{34}^{\circ }\text{C}$. Assuming ideal behaviour, calculate the density of ethylene glycol. ($K_f$ for water $=1.86{\text{K kg mol}}^{-1}$)

• A. $2.00\text{g/mL}$
• B. $1.13\text{g/mL}$
• C. $2.96\text{g/mL}$
• D. $4.32\text{g/mL}$

Answer 1

The correct option is B $1.13\text{g/mL}$

$\Delta T=\frac{K_f\times W_2\times 1000}{M{w}_2\times W_1}$
$34=1.86\times \frac{W_2\times 1000}{62\times 50}$
$W_2=56.66g$
$Volume=\frac{W_2}{d}$
$Density=\frac{56.66}{50}$
$=1.13gc{m}^{-3}$