Question

18g glucose is dissolved in 180g of water. The relative lowering of vapour pressure is ? a)1 b)1.8 c)0.01 d)0.001

Answer 1

See Below

Explanation:

Vapor Pressure lowering is governed by Raoult's law, which basically states:
`P_n = (X_n)xxP_o`
were `P_n` is the new vapor pressure, `X_n` is the mole faction of the solvent, and `P_o` is the pure solvent vapor pressure.

I think the relative lowering would be`(1 - P_n/P_o)`, which is `(1-X_n)`

`X_n = ("moles of water")/("total moles")`
`X_n = 10/10.1 = 0.99009901`

Relative Lowering:
`(1-0.99009901) = 0.00990099 = 0.01`