Difference in boiling point and freezing point of 10kg aqeous solution of urea is `100.2372^(@)C` ,then what quantity of urea dissolved in the solution ?
(`K_(b) = 0.512^(@)C ` and `K_(f) = 1.86^(@)C ` kg `mol e^(-1) ` )

Options

A. 60
B. 38.946
C. 51.65
D. 40.5

Answer

A

Explanation

`T_(b) -T_(f) =100.2372 `
`:. T_(b)^(0) + DeltaT_(b) - ( T_(f)^(0) -DeltaT_(f))= 100.2372 `
`:. 100+Delta T _(b) =( 0-DeltaT_(f)) = 100.2372`
`:. Delta T_(b) +Delta T_(f)= 0.2372`
For ureai= 1 `:. mK_(b) + mK_(f) = = 0.2372`
`:. m =( 0.2372)/( K_(b) + K_(f)) = ( 0.2372)/( 0.513 +1.86)`
`:.m= 0.1 `