Question

150 g of acetic acid was contaminated with 10.2 g ascorbic acid (C6H8O6) to lower down its freezing point by (x × 10–1)°C. The value of x is ______. (Nearest integer)

(Given : Kf = 3.9 K kg mol–1; molar mass of ascorbic acid = 176 g mol–1)

Answer 1

M.wt. of Acetic acid = 60 g

M.wt. of Ascorbic acid = 176 g

$\begin{array}{l}\Delta T_f = K_f m\end{array}$

$\begin{array}{l}\Delta T_f = \frac{3.9 \times 10.2 \times 1000}{176 \times 150}\end{array}$

\begin{array}{l}\Delta T_f =1.506\\\= 15.06 × 10^{–1}= 15\end{array}