The boiling point of an aqueous solution of a non-volatile solute is `100.15^(@)C`. What is the freezing point of an aqueous solution obtained by diluting the above solution with an equal volume of water? `[K_(b) and K_(f) "for water are 0.512 and 1.86 K" molal^(-1)]`

Options

A. `-0.544^(@C)`
B. `-0.52^(@)C`
C. `-0.272^(@)C`
D. `-1.86^(@)C`

Explanation

For the same solution
`(DeltaT_(f))/(DeltaT_(b))=(K_(f))/(K_(b))impliesDeltaT_(f)=(K_(f))/(K_(b))xxDeltaT_(b)" ":. DeltaT_(f)=(0.15xx1.86)/0.512=0.545`
On diluting the solution to double
`DeltaT_(f) prop 1/("Weight of solvent")`
`DeltaT_(f)=0.545/2=0.272" ":.` Freezing point `=-0.272`