The plot of osmotic pressure ( $\pi$ ) vs concentration $\left(\mathrm{mol} \mathrm{L}^{-1}\right)$

Question

The plot of osmotic pressure ( $\pi$ ) vs concentration $\left(\mathrm{mol} \mathrm{L}^{-1}\right)$ for a solution gives a straight line with slope $25.73 \mathrm{~L}^{-1}$ bar $\mathrm{mol}^{-1}$. The temperature at which the osmotic pressure measurement is done is (Use $R =0.083 \mathrm{~L}$ bar $\mathrm{mol}^{-1} \mathrm{~K}^{-1}$ )

Professor PC Thomas Classes · Answer

(a) : As we know, $\pi=C R T$ \ The plot of $\pi$ (osmotic pressure) vs concentration will give (On comparing with straight line equation 
$y=m x+C$ ) Slope $=(m)=R T$ $\begin{aligned} & 25.73=R T \ & T=\frac{25.73}{R}=\frac{25.73}{0.083}=310 \mathrm{~K} \ & T=310 \mathrm{~K} 	ext { or } 37^{\circ} \mathrm{C}\end{aligned}$