Question

A solution containing $10.2$glycerin per litre is isotonic with a 2% solution of glucose. What is the molecular mass of glycerin?

• A. $91.8g$
• B. $1198g$
• C. $83.9g$
• D. $890.3g$

Answer 1

Answer: (A)

$91.8g$

Answer 2

$\pi_{glycerine} = \pi_{glu\cos e}$

$\frac{n_{1}}{V_{1}}RT = \frac{n_{2}}{V_{2}}RT$

$\frac{10.2}{M} \times \frac{1}{1} = \frac{2}{180} \times \frac{1000}{100}$

$\Rightarrow M = \frac{10.2 \times 18}{2} = 91.8g$

(Density of water = $1g/cm^{3}$)