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

Options

A. `-7.44^(@)C`
B. `-5.58^(@)C`
C. `-3.72^(@)C`
D. `-2.79^(@)C`

Answer

C

Explanation

Freeing point of mixture is `M_(1)V_(1) + M_(2)V_(2) = M_(3)V_(3)`
`K_(f) = Delta T_(f) // m = 1.86 //0.1 = 18.6`
`0.1 xx V + 0.3 xx V = M_(3) xx 2V`
or `M_(3) = 0.2, Delta T_(f) = 18.6 xx 0.2 = 3.72^(@)`
`T_(f) = 3.72^(@) C`