moles of methanol = moles of water = 1
total moles = 2
mole fraction of each = 0.5
vapour pressure of solution = Pm Xm + PwXw
                                            Â
= 13.02 x 0.5 + 3.20 x 0.5
                                            Â
= 8.11 kPa
vapour pressure of solution   = 8.11
kPa
2)
here in methanol NaCl does not dissolve .
so NaCl i value = 1
in water will give 2 ions .
so NaCl i value = 2 .
vapour pressure is directly proportional to i value.
NaCl i value is more in water. in that vapour pressure is most
depressed.