Question

Which is the correct relation between osmotic pressure of 0.1 M $NaCl$ solution & 0.1 M $N{a}_{2}S{O}_4$ solution?

• A. The osmotic pressure of $N{a}_{2}S{O}_4$ is less than $NaCl$ solution
• B. The osmotic pressure of $N{a}_{2}S{O}_4$ is more than $NaCl$ solution
• C. The osmotic pressure of $N{a}_{2}S{O}_4$ is 1.5 times that of $NaCl$ solution
• D. The osmotic pressure of $NaCl$ is 1.5 times that of $N{a}_{2}S{O}_4$ solution

Answer 1

Answer: (C)

The osmotic pressure of $N{a}_{2}S{O}_4$ is 1.5 times that of $NaCl$ solution

$NaCl\to N{a}^{+}+C{l}^{-}$

${\pi }_{NaCl}=iCRT$

$=2\times 0.1\times R\times T$

$=0.2RT$

$N{a}_{2}S{O}_4\to 2N{a}^{+}+S{O}_4^{2-}$

${\pi }_{N{a}_{2}S{O}_4}=3\times 0.1\times R\times T=0.3RT$

$\therefore \frac{{\pi }_{N{a}_{2}S{O}_4}}{{\pi }_{NaCl}}=1.5$

Hence, option $C$ is correct.