Question

Exactly 100g of water contains 1g urea and 2g sucrose at 300K. The vapour pressure of solution if
vapour pressure of pure water at 300K is 23.756 mm of Hg is

1) 23.66 mm
2) 23.82mm
3) 23.01mm
4) 23.96mm

Answer 1

Answer:

Mass of urea = 5 g

Mass of water = (100-5) = 95 g

No. of moles of urea =

60

5

=0.083

No. of moles of water =

18

95

=5.278

Total number of moles =5.278+0.083

=5.361

Mole fraction of solvent =

5.361

5.278

P

s

= Mole fraction of solvent ×P

0

=

5.361

5.278

×23.5=23.14mm