$2C_{6}H_{5}NO_{2}\xrightarrow{Zn/NaOH}X$
X in the above reaction is :

Question

Accepted Answer

In the given reaction, $2C_{6}H_{5}NO_{2}\xrightarrow{Zn/NaOH}X$, the compound X is identified as Option 3: $C_{6}H_{5}NH-NH-C_{6}H_{5}$.

1. **Explanation for Option 3:**
   - The reaction involves the reduction of nitrobenzene ($C_{6}H_{5}NO_{2}$) using zinc (Zn) in the presence of sodium hydroxide (NaOH). This specific set of reagents and conditions is known to facilitate the reduction of nitro groups to form azoxy compounds.
   - In this context, two molecules of nitrobenzene undergo reduction and coupling to form azoxybenzene ($C_{6}H_{5}NH-NH-C_{6}H_{5}$), which is characterized by the presence of the -NH-NH- linkage between two phenyl groups.
   - This reaction pathway is consistent with the formation of azoxy compounds, which are typically produced under these conditions.

2. **Explanation for why other options are incorrect:**
   - **Option 1: $C_{6}H_{5}NH_{2}$ (Aniline)**
     - Aniline is typically formed by the complete reduction of nitrobenzene using stronger reducing agents like iron (Fe) and hydrochloric acid (HCl) or catalytic hydrogenation. The presence of Zn/NaOH does not fully reduce the nitro group to an amine under these conditions.
   
   - **Option 2: $C_{6}H_{5}NHOH$ (Phenylhydroxylamine)**
     - Phenylhydroxylamine is an intermediate in the reduction of nitrobenzene, but it is not the final product under the given reaction conditions. The reaction proceeds further to form azoxybenzene rather than stopping at the hydroxylamine stage.
   
   - **Option 4: $C_{6}H_{5}N=N-C_{6}H_{5}$ (Azobenzene)**
     - Azobenzene is formed through the reduction of nitrobenzene under different conditions, typically involving more controlled or catalytic processes. The Zn/NaOH system is more conducive to forming azoxybenzene rather than azobenzene.

In conclusion, the correct product of the reaction given the specified conditions is azoxybenzene, which corresponds to Option 3: $C_{6}H_{5}NH-NH-C_{6}H_{5}$. This explanation aligns with the known chemistry of nitrobenzene reduction using zinc and sodium hydroxide.