Question

The freezing point of 0.1 M solution of glucose is `-1.86^(@)C`. If an equal volume of 0.3 M glucose solution is added, the freezing point of the mixture will be
A. `-7.44^(@)C`
B. `-5.58^(@)C`
C. `-3.72^(@)C`
D. `-2.79^(@)`

Answer 1

Correct Answer - c
`K_(f) = DeltaT_(f)//M = 1.86//0.1 = 18.6`
`0.1xxV + 0.3 V = M_(3)xx2V`
or `M_(3) = 0.2`
`DeltaT_(f) = 18.6xx0.2 = 3.72^(@)C`
`T_(f) = 18.6xx0.2 = 3.72^(@)C`
`T_(f) = -3.72^(@)C`