C6H6 + CnH2n+1Cl======> C6H5-CnH2n+1 +HCl
M,compus= 12(n+6)+2n+6 g/mol
14n+78g..compus...................12n+72 gC,
100g..compus...........................90,56g
100(12n+72)= 90,56(14n+78)----> n=2----> C2H5Cl
