Which of the following aqueous solutions has highest freezing point?

Options

A. 0.1 molal `A1_(2)(SO_(4))`
B. 0.1 molal `BaCl_(2)`
C. 0.1 molal `AlCl_(3)`
D. 0.1 molal `NH_(4)CI`

Answer

D

Explanation

`DeltaT_(f)= iK_(f)m`
As m = 0.1 molal for all given solutions, thus, lower the value of i, lower will be the depression in freezing point (`DeltaT_(f)`) and higher will be the freezing point of the solution.
For `Al_(2) (SO_(4))_(3)`, i = 5
For `BaCl_(2)`, i = 3
For `AICI_(3)` , i = 4
For `NH_(4)Cl` , i = 2
Thus, 0.1 molal `NH_(4)Cl` will have highest freezing point.