Question

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

• A. The osmotic pressure of $N{a}_{2}S{O}_4$ is less than NaCI solution.
• B. The osmotic pressure of $N{a}_{2}S{O}_4$ is more than NaCI solution.
• C. Both have same osmotic pressure.
• D. None of the above

Answer 1

The correct option is B The osmotic pressure of $N{a}_{2}S{O}_4$ is more than NaCI solution.

Vant Hoff factor for dissociation -

$i=1+(n-1)\alpha$

Where

$n$ is the no. of dissociated particles

$\alpha =$ degree of dissociation
also,

$NaCl=>n=2$

$CaC{l}_2=>n=3$

$K_4\left[F\right(C{N}_6\left)\right]=>n=5$

$N{a}_{2}S{O}_4$ have more osmotic pressure than $NaCl$ solution because $N{a}_{2}S{O}_4$ gives $3$ ions.