Organic Compounds Containing Nitrogen — NEET UG practice

1. When an alkyl halide reacts with $AgCN$, the reaction proceeds through the nitrogen atom of the cyanide ion (because $Ag^+$ makes the $C-N$ bond more covalent, and nitrogen becomes the more reactive nucleophilic site), forming an isocyanide.

2. This isocyanide, ethyl isocyanide ($C_2H_5NC$), is well known for its strong, unpleasant (foul) smell.

3. Therefore, since both reactions in the question give the same foul-smelling product, $X$ must be $AgCN$ and $Z$ must be $C_2H_5NC$.

4. In contrast, $KCN$ reacts through the carbon atom of the cyanide ion, giving a nitrile ($C_2H_5CN$), which does not have a foul odor.

5. Hence, the answer is option A.

1. In many aromatic substitution reactions, a mixture of ortho (o-) and para (p-) isomers is formed as the two major products.

2. These isomers have different boiling points because the more symmetrical para isomer packs and interacts differently than the ortho isomer.

Given the boiling points,

3. Since these boiling points are sufficiently different, the mixture can be separated by carefully heating it and collecting each component as it evaporates within its own boiling range, typically under reduced pressure.

4. This technique is known as fractional distillation.

5. Hence, the answer is option A.

1. An aliphatic primary amine reacts with nitrous acid ($HNO_2$, generated in situ from $NaNO_2 + HCl$) to form an unstable diazonium salt.

2. Unlike aromatic diazonium salts, aliphatic diazonium salts are highly unstable, even at low temperature, and decompose immediately with loss of nitrogen gas.

3. The resulting ethyl carbocation quickly reacts with water present in the reaction mixture to give an alcohol.

4. This brisk evolution of nitrogen gas along with alcohol formation is actually used as a test to identify primary aliphatic amines.

5. Hence, the major product $Z$ is ethanol ($C_2H_5OH$), so the answer is option C.