Question

The nitration of benzene using a mixture of concentrated \(\mathrm{H_2SO_4}\) and concentrated \(\mathrm{HNO_3}\) gives:

• A. Benzylamine
• B. Benzene diazonium salt
• C. Nitrobenzene
• D. Phenol

Hint:

In electrophilic aromatic substitution, strong electrophiles like nitronium ion \(\mathrm{NO_2}^+\) are generated by acid mixtures; nitration of benzene forms nitrobenzene.

Answer 1

The Correct Option is C

- Nitration of benzene is an example of an electrophilic aromatic substitution reaction. - When benzene is treated with a mixture of concentrated sulfuric acid (\(\mathrm{H_2SO_4}\)) and concentrated nitric acid (\(\mathrm{HNO_3}\)), the nitration reaction occurs. - The role of \(\mathrm{H_2SO_4}\) is to generate the electrophile nitronium ion (\(\mathrm{NO_2}^+\)) from nitric acid: \[ \mathrm{HNO_3} + \mathrm{H_2SO_4} \rightarrow \mathrm{NO_2}^+ + \mathrm{HSO_4}^- + \mathrm{H_2O} \] - The nitronium ion (\(\mathrm{NO_2}^+\)) acts as the electrophile and attacks the benzene ring, substituting one hydrogen atom to form nitrobenzene. - Overall reaction: \[ \mathrm{C_6H_6} + \mathrm{NO_2}^+ \rightarrow \mathrm{C_6H_5NO_2} + \mathrm{H}^+ \] - Therefore, the product formed is nitrobenzene.