Heptane and octane form ideal solution. At `373K`, the vapour pressure of the two liquids are `105.2 kPa` and `46.8 kPa` respectively. What will be the vapour pressure, in bar, of a mixture of `25g` of heptane and `35g` of octane?

Explanation

(A) Heptane `{:((A) "Heptane" C_(7)H_(16),m_(A) = 100),((B) "Octane" C_(8)H_(18),m_(B) =114),(n_(A)=(w_(A))/(m_(A))=(25)/(100) =0.25,,n_(B) = (35)/(114) = 0.3),(x_(A) =(0.25)/(0.25 xx 0.30) =0.45,x_(B) =(0.3)/(0.25+0.30) =0.55),(=0.45,):}`
`p = p_(A)^(0) x_(A) +p_(B)^(0)x_(B)`
`= 105.2 xx 0.45 +46.8 xx 0.55`
`= 47.34 +25.74 = 73.08 kPa`