Identify the reagents A, B, C, D, E and F required for the following conversion :
`C_6 H_5 NO_2 overset(A ) to C_6 H_5 NH_2 overset(B ) to C_6 H_5 overset(+ )N_2 (Cl^-) to C_6 H_5 Cl overset(D ) to C_6 H_5 OH overset(H_2 SO_4) to E +F `

Explanation

`A to Sn + conc. HCI`.
`B to NaNO_2 + conc. HCl and 0^@C -5^@C`
`C to CuCl_2 + HCI`
`D to NaOH//HCI`
`E to 2`-hydroxy benzene sulphonic acid.
`Fto 4`-hydroxy benzene sulphonic acid.