The osmotic pressure of solutions of PVC in cyclohexanone at 300K...

Using osmotic pressure in ideal gas equation:
$\pi = {M}^{'}RT = \left(\dfrac{W / M}{V}\right)RT$

$⇒ \pi = \left(\dfrac{W}{V}\right)\left(\dfrac{1}{M}\right)RT = C\left(\dfrac{RT}{M}\right)$

$⇒ \dfrac{\pi}{C} = \dfrac{RT}{M}$

If we assume given graph between $\dfrac{\pi}{C}$ and $C$

Slope $= \dfrac{RT}{M} = \dfrac{0 . 083 \times 300}{M} = 6 \times {10}^{- 4}$

$∴ M = \dfrac{0 . 083 \times 300}{6 \times {10}^{- 4}} = \dfrac{830 \times 300}{6}$

$= 41, 500gm / mole$