Osmotic pressure of a solution is 0.0821 atm at a temperature of 300K. The concentration in mole/ litre will be

Given:

Osmotic pressure of solution $=\mathrm{\pi }=0.0821 atm$

Temperature, $T=300K$

Osmotic pressure of solution is given by the formula, $\mathrm{\pi }=\mathrm{CRT}$                    

  C = concentration in mole/litre

  R = Universal Gas Constant $=0.0821 L\left(atm\right)/mol.K$

  $\mathrm{\pi }=\mathrm{CRT}$

$$\begin{gathered} \mathrm{C}=\frac{\mathrm{\pi }}{\mathrm{RT}} \\ =\frac{0.0821}{0.0821\times 300} \\ =\frac{1}{300} \\ =0.33\times {10}^{-2} \mathrm{mole}/\mathrm{litre} \end{gathered}$$

The concentration of solution is $0.3\times {10}^{-2 }mole/litre$, making option C the correct answer.