An organic compound X ( C_6H_7N ) on treatment with NaNO_2 and...

Compound $\text{X}$ with the molecular formula $\text{C}_6\text{H}_7\text{N}$ is aniline ($\text{C}_6\text{H}_5\text{NH}_2$), which is a primary aromatic amine.

When aniline is treated with $\text{NaNO}_2$ and dilute $\text{HCl}$ at $273-278\text{ K}$, it undergoes diazotization to form benzenediazonium chloride ($\text{C}_6\text{H}_5\text{N}_2^+\text{Cl}^-$), which is the intermediate $\text{Y}$.

Benzenediazonium chloride reacts with ethanol ($\text{CH}_3\text{CH}_2\text{OH}$) to yield benzene ($\text{C}_6\text{H}_6$), which is the hydrocarbon $\text{Z}$, along with nitrogen gas and ethanal ($\text{CH}_3\text{CHO}$). The chemical equation is:

$\text{C}_6\text{H}_5\text{N}_2^+\text{Cl}^- + \text{CH}_3\text{CH}_2\text{OH} \rightarrow \text{C}_6\text{H}_6 + \text{N}_2 + \text{CH}_3\text{CHO} + \text{HCl}$

In this reaction, the diazonium salt is reduced to benzene, and ethanol is oxidized to ethanal. Therefore, ethanol acts as a reducing agent, making the conversion of $\text{Y}$ to $\text{Z}$ a redox process.

Option (A) is incorrect because $\text{X}$ is an aromatic amine, not aliphatic.

Option (B) is incorrect because the reaction is a reduction, not a nucleophilic substitution.

Option (D) is incorrect because benzenediazonium chloride is unstable at room temperature and must be kept cold ($273-278\text{ K}$).

Answer: The conversion of $\text{Y}$ to $\text{Z}$ is a redox process in which ethanol acts as a reducing agent.