An aqueous solution contain 5% by weight of urea and 10% by weight of glucose. What will be the `Delta T_(f)` of solution ? (Given that `K_(f)` for `H_(2)O` is `1.86^(@)C kg mol^(-1)`).

Answer

3

Explanation

`Delta K_(f) = K_(f) xx m`. Since solution has 5% by weight urea and 10% by weight glucose, so % by weight `= ("Weight of solute")/("Weight of solution") xx 100`
If total weight =100g, then weight of water = 85g, weight of urea =5g, weight of glucose =10g
Now, `Delta T_(1)= Delta T_("urea") + Delta T_("gluocse")`
As both are non-electrolytes, i=1, so
`Delta T= (1000 xx 1.86 xx 5)/(60 xx 85)+ (1000 xx 1.86 xx 10)/(180 xx 85)= 3.04^(@)C`