chemical process

1.Chlorobenzene (C6H5Cl) is an important solvent and intermediate in the production of many other chemicals. It is produced by bubbling chlorine (Cl2) gas through liquid benzene (C6H6) in the presence of a catalyst to produce C6H5Cl and HCl. In an undesired side reaction, the product is further chlorinated to produce dichlorobenzene (C6H4Cl2), which can be further chlorinated to produce trichlorobenzene (C6H3Cl3).

The reactions are as follow:
C6H6 (l) + Cl2(g) → C6H5Cl (l) + HCl (g)
C6H5Cl (l) + Cl2(g) → C6H4Cl2(l)+ HCl (g)
C6H4Cl2 (l)+ Cl2 (g) → C6H3Cl3(l) + HCl (g)

The feed to a chlorination reactor consists of pure liquid benzene and a technical grade of chlorine gas (98 wt% of Cl2, the rest is a gaseous impurity with an average molecular weight of 25.0). The liquid output from the reactor contains 65.0 wt% C6H6, 32.0 wt% of C6H5Cl, 2.5 wt% of C6H4Cl2, and 0.5 wt% of C6H3Cl3. The gaseous output contains only HCl and the impurity that enters with chlorine gas.

(a) Determine the percentage by which benzene is fed in excess, and the conversion of benzene. (Hints: use liquid output as a basis).
(b) Determine the yield of chlorobenzene. (Yield is defined as the ratio of the amount produced to the theoretical amount that could have been produced).
(c) Determine the mass ratio of the gas feed to the liquid feed.
(d) In this process, why would benzene be fed in excess?