Calcuate the mass of non-volatile solute having molecoles mass 40, which should be dissolved in 57 gm octane to reduce its vapour pressure to 80%:

Options

A. `47.2g`
B. `5g`
C. `106.2g`
D. None of these

Answer

2

Explanation

`P_(s)=((80)/(100))P^(@),w= ?`
`M_("solute")=40,w=114g,M_("solvent")=114`
`rArr" "(P^(@)-P_(s))/(P_(s))=(w)/(M_("solute"))xx(M_("solvent"))/(w)" "or" "(P^(@)-(80//100)P^(@))/((80//100)P^(@))=(wxx114)/(40xx57)`