Question

The decrease in the freezing point of an aqueous solution of a substance is $1.395k$ and that in the
freezing point of benzene solution of the same substance is $1.280k$. Explain the difference in $\Delta T$.
The substance:

• A. dissociates in the aqueous solutio as well as in the benzene solution
• B. forms complex in solution
• C. associates in the benzene solution
• D. dissociates in the aqueous solution and not in the benzene solution

Answer 1

The correct option is D dissociates in the aqueous solution and not in the benzene solution

We know, $\Delta T_f=K_{f}m$

Now, since the depression in freezing point for the aqueous solution is more in comparison to the benzene solution when conditions are the same, this means the change is due to $"i"$.

$\Delta T_f$ will be more for the solution where $"i"$ is more, i.e. dissociation takes place.