which of the solutions wil have a lower vapour pressure and why?

1. a 5% solution of cane sugar

2. a 5% solution of urea

Lowering of vapour pressure depends on number of moles of solute present.
 
 
Molar mass of sugar is higher than Urea, so number of moles (in 5% solution) of urea is higher than sugar.
Thus lowering of vapour pressure in a 5% solution of urea will be more.