Clch2-ch2cl-> ch2-> с6н6-> c6h5ch2-ch3-> c6h5cooh-> c6h4brcooh

1)ClCH2-CH2Cl+2KOH=C2H2+2KCl+2H2O

2)3C2H2=C6H6

3)C6H6+Cl2=C6H5Cl+HCl

C6H5Cl+2Na+Cl-CH2-CH3=C6H5-CH2-CH3+2NaCl

C6H5-CH2-CH3+KMnO4+H2SO4=C6H5-COOH+K2SO4+MnSO4+H2O

C6H5-COOH+Br2=C6H4Br-COOH+HBr