Question

Which of the following exhibits the greatest freezing point lowering per mole of solute?

• A. 0.01 m NaCl
• B. 0.1 m NaCl
• C. 0.01 m C₂H₅OH
• D. 0.1 m C₂H₅OH

Answer 1

Answer: (B)

Lowering in freezing point is a colligative property, colligative property depends on the number of molecule atom or ions and molality. In 0.1 m NaCl. Molality is maximum out of four and NaCl dissociates into $N{a}^{+},C{l}^{-}$ (i = 2).

Colligative property $\propto m\times i$

So, 0.1 m NaCl > 0.1 m $C_2{H}_{5}OH$ > 0.01 m NaCl > 0.01 m $C_2{H}_{5}OH$