Question

Calculate the cryoscopic constant of a solvent if depression in freezing point of \(0\cdot 3\) m solution of nonelectrolyte is \(0\cdot 48\) K

• A. \(1\cdot 1\text{ K kg mol}^{-1}\)
• B. \(1\cdot 6\text{ K kg mol}^{-1}\)
• C. \(2\cdot 2\text{ K kg mol}^{-1}\)
• D. \(2\cdot 6\text{ K kg mol}^{-1}\)

Hint:

Use the depression equal to Kf times molality.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
For a non-electrolyte, the depression in freezing point is directly proportional to molality: \(\Delta T_f = K_f\, m\).

Step 2: Calculation:
\[ K_f = \frac{\Delta T_f}{m} = \frac{0.48}{0.3} = 1.6\text{ K kg mol}^{-1} \]
Only option (B) satisfies this relation.

Final Answer:
The cryoscopic constant is 1.6 K kg/mol, option (B). \[ \boxed{1.6\text{ K kg mol}^{-1}} \]