Question

The depression in freezing point of a solution of molality \(0.01\ mol\ kg^{-1}\) is highest with respect to which of the following solvents? (Values of \(K_f\) are given in brackets)

• A. Water \((1.86)\)
• B. Benzene \((5.12)\)
• C. Carbon tetrachloride \((31.8)\)
• D. Cyclohexane \((20.0)\)

Hint:

For solutions having the same molality, \[ \Delta T_f = K_fm \] Hence, the solvent with the largest \(K_f\) value exhibits the greatest depression in freezing point.

Answer 1

The Correct Option is C

Step 1: Compare K_f values directly.
For equal molality and i, ΔT_f ∝ K_f. Values: H₂O = 1.86, C₆H₆ = 5.12, C₆H₁₂ = 20.0, CCl₄ = 31.8. CCl₄ has the largest K_f, so largest depression.

Step 2: Final Answer:
Carbon tetrachloride (option 3).