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°C. Assuming ideal behaviour, calculate the density of ethylene glycol in ${\text{g/cm}}^3$ $(K_f\text{for water}=1.86{\text{K Kg mol}}^{-1})$.

Answer 1

Volume of Ethylene glycol $=50{\text{cm}}^3$

$K_f=1.86{\text{K kg mol}}^{-1}$

Mass of glycol (w) = V × d = 50 × d g

Mass of water (W) = $50\text{g}$

$\Delta T_f={34}^{\circ }\text{C}$
$\Delta T_f=\frac{K_f\times w\times 1000}{m\times W}$

$\Rightarrow 34=\frac{1.86\times 50\times d\times 1000}{62\times 50}$

$\Rightarrow d=1.133{\text{g/cm}}^3$