The vapour pressure of ethly acetate and ethly propionate are72.8mm abd 27.7mm of Hg respectively. A solution is prepared by mixing 25 g ethly acetate and 50 g of ethly propionate. Assuming to be ideal, calculate its vapour pressure.

Explanation

No. of moles of `CH_(3)COOC_(2)h_(5)(n_(B))=("Mass of" CH_(3)COOC_(2)h_(5))/("Molar mass")`
`((25g))/((88g mol^(-1))=0.284 mol`
No. of moles of `C_(2)H_(5)COOC_(2)H_(5) (n_(A))=("Mass of" C_(2)H_(5)COOC_(2)H_(5))/("Molar mass")`
`=((50g))/((102g mol^(-1))=0.49 mol`
Mjole fraction of ethyl acetate `(x_(B)) =n_(B)/((n_(A)+n_(B))=((0.284 mol))/((0.28l4mol+0.49 mol))=0.37 `
Mole fraction of ethyl propionate `(x_(A))=n_(A)/(n_(A)+n_(B))=((0.49 mol))/((0.284 mol+0.49))=0.63`
Vapour pressure of ethly acetate `(P_(B)^(@))=72.8 mm`
Vapour pressure of ethly propionate `(P_(A)^(@))=27.7 mm `
Vapour pressure of ethyl acetate in solution `(P_(B))=P_(A)^(@)x_(A)=(72.8mm)xx0.37=26.94 mm`
Vapour pressure of ethyl propionate in solution `(P_(A))==P_(A)^(@)X_(a)=(27.7 mm)xx0.63=12.45 mm`
Total vapour pressure of solution =`P_(B)+P_(A)`
=26.94mm+17.45mm=44.39 mm