`0.15`g of a subatance dissolved in `15`g of solvent boiled at a temperature higher at `0.216^(@)`than that of the pure solvent. Calculate the molecular weight of the substance. Molal elecation constant for the solvent is `2.16^(@)C`

Options

A. `216`
B. `100`
C. `178`
D. None of these

Answer

B

Explanation

Here it is given that
`{:(w=0.15g,DeltaT_(b)=0.216^(@)C),(W=15g,K_(b)=2.16^(@)C):}`
`m=?`
Substituting values in the experssion , we have
m=`(1000xxk_(b)xxw)/(DeltaT_(b)xxW)`
`m=(1000xx2.16xx0.15)/(0.216xx15)=100`