Aniline cannot be obtained by :

Options

A. `C_(6)H_(5)NO_(2)underset("Electrolysis")overset(conc.H_(2)SO_(4))(to)`
B. `C_(6)H_(5)Clunderset(Delta)overset(NaNH_(2))(to)`
C. `C_(6)H_(5)COClunderset((H_2O))overset(NaN_(3))(to)`
D. `C_(6)H_(5)OHunderset(DryZnCl_(2))overset(NH_(3))(to)`

Answer

To determine how aniline cannot be obtained, we need to analyze the options provided. Aniline is an aromatic amine with the formula C6H5NH2. Let's evaluate the options step by step.

### Step 1: Analyze the first option - Electrolysis of nitrobenzene with concentrated H2SO4
- When nitrobenzene (C6H5NO2) undergoes electrolysis in the presence of concentrated sulfuric acid (H2SO4), it gets reduced.
- The reduction of nitrobenzene typically leads to the formation of hydroxylamine (NH2OH) initially.
- However, further reduction and rearrangement can lead to the formation of nitrophenol (C6H4(OH)(NO2)), not aniline (C6H5NH2).
- Therefore, aniline cannot be obtained from this reaction.

### Step 2: Analyze the second option - Curtius reaction
- The Curtius reaction involves the conversion of an azide (R-N3) to an amine (R-NH2) by the release of nitrogen gas (N2).
- In this reaction, the azide acts as a precursor, and when it decomposes, it releases N2 and forms the corresponding amine.
- If we consider the reaction where an azide is treated with an appropriate nucleophile (like phenyl isocyanate), it can lead to the formation of aniline.
- Thus, aniline can be obtained from this reaction.

### Conclusion
Based on the analysis:
- Aniline cannot be obtained by the electrolysis of nitrobenzene with concentrated H2SO4, as this leads to the formation of nitrophenol instead.
- Therefore, the correct answer is the first option.