An aqueous solution contaning `5%` by weight of urea and `10%` weight of glucose. What will be its freezing point? `(K'_(f) for H_(2)O "is" 1.86^(circ) mol^(-1) kg)`

Options

A. `-3.03.^(@)C`
B. `3.03.^(@)C`
C. `1.02.^(@)C`
D. `-1.02.^(@)C`

Explanation

Total molality =
`((5)/("mol. Wt glucoss")+(10)/("mol. Wt of urea"))xx(1000)/(100)`
`=((5)/(180)+(10)/(60))xx(1000)/(100)rArr (5+30)/(180)xx(1000)/(100)rArr (35)/(180)xx(1000)/(100)`
Freezing point of solution
`= (0-(350)/(180)xx1.86).^(@)C rArr - 3.03.^(@)C`