Question

Aniline on heating with $X$ in the presence $KOH$ gives a product with a very bad smell. Identify $X$ .
A. $C{H_3}Cl$
B. $CC{l_4}$
C. $CHC{l_3}$
D. ${C_2}{H_5}Cl$

Answer 1

According to the question the reaction is as follows: ${\text{Aniline + X + KOH}} \to {\text{ smelly substance}}$
Aniline is an organic compound containing a phenyl group attached to an amino group in its structure having molecular formula. It is classified as amine. It has its major application in the manufacturing of industrial chemicals and it is used as the precursors to polyurethane production.

Complete step by step answer:
Aniline is the simplest amine and for the detection of primary, secondary and tertiary amines certain tests are performed. In order to detect the primary amines carbylamine reaction is performed.
The presence of primary amine is detected with the production of isocyanides as the product which has the pungent smell as its identification characteristic. The detection reaction takes place when aniline in the presence of potassium hydroxide ${\text{KOH}}$ is heated with chloroform ${\text{CHC}}{{\text{l}}_3}$. If there is presence of primary amine in reaction the smelly product isocyanides ${{\text{C}}_6}{{\text{H}}_4}{\text{NC}}$ will be formed.
${{\text{C}}_6}{{\text{H}}_5}{\text{ + CHC}}{{\text{l}}_3}{\text{ + KOH}} \to {\text{ }}{{\text{C}}_6}{{\text{H}}_4}{\text{NC}}$
So according to the question: ${\text{Aniline + X + KOH}} \to {\text{ smelly substance}}$, here ${\text{X }}$ represents the chloroform ${\text{CHC}}{{\text{l}}_3}$ and the smell producing substances is ${{\text{C}}_6}{{\text{H}}_4}{\text{NC}}$.
Chloroform has the great property to dissolve the substances in it, hence it is used as a solvent in chemistry.
Potassium hydroxide is commonly known as caustic soda, which has its application in manufacturing industries and because of its basic nature it is used as a reaction neutralizer in some reactions.

So, the correct answer is Option C .

Note:
Cyanide and isocyanide are two different organic compounds because of different functional group. The attachment criteria is different for both the groups. In cyanide the attachment is through carbon atom and the isocyanide has attachment to the group through nitrogen atom.