Feed $=1000kg$;$A$ benzene $)=(78$ nitrobenzenc $(M{M}_{1}123).x_F=0\mathrm{.}5=>$ mol. wt of feed $=(0\mathrm{.}5)(78)+(0\mathrm{.}5)(123)=100\mathrm{.}5.$

Moles of beed, $F=\frac{1000}{100\mathrm{.}5}=9\mathrm{.}95$kmol.

Residue in the still $=k$ kmol, mole fraction of beuzene $=x_{}$; mass of residue $=W[78x_{}+123(1-x_{})]=500=>W=\frac{500}{?}.$

Use Eq ${?}_1(7\mathrm{.}516),$ put the values of $F,x_F$ and $)=(7\mathrm{.}0.$

Solvig, $x_{}=0\mathrm{.}141,W=4\mathrm{.}286.$ Use Eq $7\mathrm{.}52$ formatesial balance $(9\mathrm{.}95)(0\mathrm{.}5)=(5\mathrm{.}664)y_{D,av}+(4\mathrm{.}286)(0\mathrm{.}141)=>(0\mathrm{.}7),y_{D,av}=0\mathrm{.}77$

The repossed concentration of benzene iu iu the accumulated condensate is not accirate.