Question

12 g of a nonvolatile solute dissolved in 108 g of water produces the relative lowering of vapour pressure of 0.1. The molecular mass of the solute is ______.

Options

• 80

• 60

• 20

• 40

Answer 1

12 g of a nonvolatile solute dissolved in 108 g of water produces the relative lowering of vapour pressure of 0.1. The molecular mass of the solute is 20.

Explanation:

`("P"^0 - "P"_"s")/"P"^0 = "n"/"N" = "w"/"m" xx "M"/"W"`

0.1 = `12/"m" xx 18/108`

m = `(12 xx 18)/(0.1 xx 108)`

m = 20