Question

The solution containing $4.0\, gm$ of a polyvinyl chloride polymer in $1$ litre of dioxane was found to have an osmotic pressure $6.0 \times 10^{-4}$ atmosphere at $300 \,K$, the value of $R$ used is $0.082$ litre atmosphere $mole^{-1}K^{-1}$ The molecular mass of the polymer was found to be

• A. $3.0 \times 10^{2}$
• B. $1.6 \times 10^{5}$
• C. $5.6 \times 10^{4}$
• D. $6.4 \times 10^{2}$

Answer 1

Answer: (B)

$\pi \,V = \frac{w}{m} RT$
$\therefore 6\times 10^{-4} \times 1 =\frac{4}{m} \times 0.0821 \times 300$
$\Rightarrow m=1.64 \times 10^{5}$