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54
Subjective

A primary amine, $\mathrm{RNH}_2$ can be reacted with $\mathrm{CH}_3-\mathrm{X}$ to get secondary amine, $\mathrm{R}-\mathrm{NHCH}_3$ but the only disadvantage is that $3^{\circ}$ amine and quaternary ammonium salts are also obtained as side products. Can you suggest a method where $\mathrm{RNH}_2$ forms only $2^{\circ}$ amine?

Explanation

$$\mathrm{\mathop {RN{H_2}}\limits_{\Pr imary\,a\min e} \mathrel{\mathop{\kern0pt\longrightarrow} \limits_{Carbyla\min e\,reaction}^{KOH/CHC{l_3}}} \mathop {RNC}\limits_{Alkyl\,Iso\,cyanide} \buildrel {{H_2}/Pd} \over \longrightarrow \mathop {RNHC{H_3}}\limits_{Secondary\,a\min e}}$$

Primary amines show carbylamine reaction in which two H -atoms attached to N -atoms of $\mathrm{NH}_2$ are replaced by one C-atom. On catalytic reduction, isocyanide (formed) produces secondary amine and not tertiary or quaternary salts.

55
Subjective

Complete the following reaction.

Explanation

The reaction exhibits azo-coupling reaction of phenols. Benzene diazonium chloride reacts with phenol in such a manner that the para position of phenol is coupled with diazonium salt to form p-hydroxy azobenzene.

56
Subjective

Why is aniline soluble in aqueous HCl ?

Explanation

Aniline is soluble in aqueous HCl due to formation of ionic anilinium chloride.

57
Subjective

Suggest a route by which the following conversion can be accomplished.

Explanation

Complete conversion can be performed as

58
Subjective

Identify A and B in the following reaction.

Explanation

Complete conversion can be performed as