A solution of urea in water freezes at `-0.400^@C`. What will be the boiling point of the same solution if the depression and elevation constants for water are 1.86 deg kg `mol^(-1)` and 0.512 deg kg `mol^(-1)` respectively?

Explanation

We have the relationships:
`DeltaT_b=(K_bn_2)/w_1` ..(i)
And`DeltaT_"f"=(K_"f"n_2)/w_1` ..(ii)
Where, `n_2` is the number of moles of the solute, and `w_1` is the mass of solvent in kg
Dividing equation (i) by equation (ii),
`(DeltaT_b)/(DeltaT_"f")=K_b/K_"f"`
or `DeltaT_b=(DeltaT_"f"xxK_b)/K_"f"=(0.4xx0.512)/1.86``^@C=0.11^@C`
Then, Boiling point of the urea solution `=100^@C+0.11^@C=100.11^@C`