Question

Identify correct A, B and C in the reaction sequence given below :

• A.

  

• B.

  

• C.

  

• D.

  

Hint:

Nitration gives nitrobenzene (A); the nitro group is a meta director so chlorination with Cl2/AlCl3 gives 3-chloronitrobenzene (B); Fe/HCl reduces the nitro group to an amino group giving 3-chloroaniline (C).

Answer 1

The Correct Option is B

Step 1: conc. \(\mathrm{HNO_3}\) + conc. \(\mathrm{H_2SO_4}\), heat: nitration of benzene gives nitrobenzene (A).
Step 2: \(\mathrm{Cl_2}\), anhydrous \(\mathrm{AlCl_3}\): electrophilic chlorination. The \(\mathrm{-NO_2}\) group is strongly deactivating and a meta director, so Cl enters the meta position: 1-chloro-3-nitrobenzene (B).
Step 3: Fe/HCl: reduces \(\mathrm{-NO_2}\) to \(\mathrm{-NH_2}\) without touching the aryl C-Cl bond: 3-chloroaniline (C).
This matches option (2): A = nitrobenzene, B = m-chloronitrobenzene, C = m-chloroaniline.
Answer: (2) A = nitrobenzene, B = 3-chloronitrobenzene, C = 3-chloroaniline