Question

The boiling point fo water `(100^(@)C` become `100.52^(@)C`, if `3` grams of a nonvolatile solute is dissolved in `200 ml` of water. The molecular weight of solute is
(`K_(b)` for water is `0.6 "K.kg mol"^(-1)`)
A. `12.2 "g mol"^(-1)`
B. `15.4 "g mol"`
C. `17.3 "g mol"^(-1)`
D. `20.4 "g mol"`

Answer 1

Correct Answer - C
First boiling point of water `=100^(@)C`
Final boiling point of water `= 100.52^(@)`
`w=3g,W=200g,K_(b)=0.6kg^(-1)`
`DeltaT_(b)=100.52-100=0.52^(@)C`
`m=(K_(b)xxwxx1000)/(DeltaT_(b)xxW)`
`=(0.6xx3xx1000)/(0.52xx200)=(1800)/(104)=17.3`