(a) Explain the following :
(i) Henry's law about dissolution of a gas in a liquid
(ii) Boiling point elevation constant for a solvent
(b) A solution of glycerol `(C_(3)H_(8)O_(3))` in water was prepared by dissolving some glycerol in 500 g of water . This solution has a boiling point of `100.42 ^(@)C` . what mass of glycerol was dissolved to make this solution ? (`K_(b)` for water = `0.512` K kg `mol^(-1)`)

Explanation

(a) (i) The most commonly used form of Henry is law states that the partial pressure of the gas is vapour phase (P) is proportional to the male fraction of the gas (X) in the solution and is expressed as : `P = K_(H)X`
Boiling point elevation constant in the elevation of boiling point of a solution when the concentration of solution is one molal.
(b) `DeltaT_(b) = 100.42 = 100 = 0.42^(@)C`
`K_(b) = 0.512 K ` kg `mol^(-1)`
`DeltaT_(b) = Kb xx m`
`M(C_(3)H_(8)O_(3)) = 92` gm `mol^(-1)`
`0.42 = (W xx 1000)/(92 xx 500) xx 0.512`
`W = 37.73` gm.