Question

A solution containing $4g$ of a non-volatile organic solute per $100mL$ was found to have an osmotic pressure equal to $500cm$ of mercury at ${27}^{o}C$. The molecular weight of solute is:

• A. $14.97$
• B. $149.7$
• C. $1697$
• D. $1.497$

Answer 1

Answer: (B)

$149.7$

Let us consider the equation:

$\pi V_2=\frac{W_2}{M{w}_{2}RT}$

Putting all given values in above equation.we have

$\frac{500}{76}\times \frac{100}{1000}=\frac{4}{M{w}_2}\times 0.0821\times 300$

$⟹M{w}_2=149.7$.

Hence, the correct option is $B$