Question

Which of the following solution will have highest freezing point depression?

• A. 1 M glucose
• B. 1 M sucrose
• C. 1 M urea
• D. 1 M KCl

Hint:

Electrolytes show greater colligative effects due to dissociation into ions.

Answer 1

The Correct Option is D

Step 1: Understanding freezing point depression.
Freezing point depression is a colligative property and depends on the number of particles present in solution.

Step 2: Role of Van’t Hoff factor.
\[ \Delta T_f = i K_f m \] where \( i \) is the Van’t Hoff factor.

Step 3: Comparing the solutions.
Glucose, sucrose, and urea are non-electrolytes and do not dissociate, so \( i = 1 \).
KCl dissociates into \( \mathrm{K^+} \) and \( \mathrm{Cl^-} \), so \( i = 2 \).

Step 4: Conclusion.
Since KCl produces the maximum number of particles, it shows the highest freezing point depression.