Question

Identify the correct relation between depression in freezing point and freezing point of pure solvent.

• A. T\(^0\) = T \(\times\) \(\Delta T_f\)
• B. T\(^0\) = \(\Delta T_f\) - T
• C. T\(^0\) = T - \(\Delta T_f\)
• D. T\(^0\) = \(\Delta T_f\) + T

Hint:

The depression in freezing point is always added to the freezing point of the pure solvent to find the freezing point of the solution.

Answer 1

The Correct Option is D

Step 1: Understanding freezing point depression.
The depression in freezing point (\(\Delta T_f\)) is the difference between the freezing point of the pure solvent and the freezing point of the solution. The formula for freezing point depression is: \[ T_0 = T + \Delta T_f \] where \(T_0\) is the freezing point of the solution, \(T\) is the freezing point of the pure solvent, and \(\Delta T_f\) is the depression in freezing point.

Step 2: Analyzing the options.
(A) T\(^0\) = T \(\times\) \(\Delta T_f\): This is incorrect. The relation is additive, not multiplicative.
(B) T\(^0\) = \(\Delta T_f\) - T: This is incorrect. It does not correctly represent the relation between freezing point and depression.
(C) T\(^0\) = T - \(\Delta T_f\): This is incorrect. The freezing point depression is added to the pure solvent's freezing point.
(D) T\(^0\) = \(\Delta T_f\) + T: Correct — This is the correct relation for freezing point depression.

Step 3: Conclusion.
The correct answer is (D) T\(^0\) = \(\Delta T_f\) + T.