Question

A solution contain $8g$ of a carbohydrate in $100g$ of water has a density $1.025$ g/mL and an osmotic pressure of $5$ atm at ${27}^{\circ }C$. What is the molar mass of the carbohydrate?

• A. $387$
• B. $374$
• C. $3740$
• D. None of these

Answer 1

The correct option is B $374$

(b) 8 g of carbohydrate is present with 100 g of water in solution
or 108 g solution contains 8 g of carbohydrate;
$V_{solution}=\frac{108}{1.025}\times {10}^{-3}$
$\pi =\frac{n}{v}\times R\times T$
$\Rightarrow \frac{8}{M}\times \frac{1.025}{108}\times 1000\times 0.0821\times 300=5$;
$M=374g/mol$