Benzene and toluene form nearly ideal solution . At 313 K the vapour pressure of benzene and toluene are 160 mm and 60 mm of Hg respectively. Calculate the total pressure of the solution made by mixing their equal masses at 313 K.

Explanation

let `n_B = n_T = x`
`:. ` (mola fraction of benzene) `x_B = n_B/(n_B + n_T)= (x)/(x+x) =x/(2x) = 1/2`
`:.` (mole fraction of Toluene) `x_T=1 - x_B =1 -1/2 =1/2`
`P_B^@ =160` mm of `Hg , P_T^@ = 60` mm of Hg
`P_("solution")=p_B^@ xx"x"_B+p_T^@ xx"x"_T`
`=[160 xx1/2 +60xx1/2]` mm of Hg
`=220/2 "mm of Hg"=110 `mm of Hg