NEET Practice Questions (MCQs) with Answers & Solutions

(b) -CN and -NC are different functional groups.

(b) ${\mathrm{CH}}_3\mathrm{COOH}\stackrel{{\mathrm{NH}}_3}{\to }{\mathrm{CH}}_3{\mathrm{COONH}}_4\stackrel{∆}{\to }{\mathrm{CH}}_3{\mathrm{CONH}}_2\stackrel{{\mathrm{P}}_2{\mathrm{O}}_5}{\to }{\mathrm{CH}}_3\mathrm{CN}\stackrel{\mathrm{Na}+{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}}{\to }{\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{NH}}_2$

 As the number of alkyl groups increases, the electron density on nitrogen atom also increases, so the basic character increases but $3°$ amines are less basic than $2°$ amines due to steric hindrance of $3°$ amines, so the correct order of basicity is 

               Ammonia<$1°<3°<2°$

${\mathrm{NH}}_3<{\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{NH}}_2<({\mathrm{C}}_2{\mathrm{H}}_5{)}_3\mathrm{N}<({\mathrm{C}}_2{\mathrm{H}}_5{)}_2\mathrm{NH}$

(c) ${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{NH}}_2 \underset{0°\mathrm{c}}{\overset{{\mathrm{NaNO}}_2+\mathrm{HCl}}{\to }}{\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{N}}_2\mathrm{Cl}$

 Order of basic nature in a aqueous solution on the basis of K_b.

$({\mathrm{CH}}_3{)}_2\mathrm{NH}>{\mathrm{CH}}_3{\mathrm{NH}}_2>({\mathrm{CH}}_3{)}_3\mathrm{N}>{\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{NH}}_2$

(a) Trinitrobenzene is an explosive compound formed during nitration of C₆H₆ with fuming HNO₃.

(a) ${\mathrm{CH}}_3-\mathrm{N}\equiv \mathrm{C} +\hspace{0.17em}4\mathrm{H} \stackrel{{\mathrm{LiAlH}}_4}{\to }{\mathrm{CH}}_3{\mathrm{NHCH}}_3$

                                         Dimethylamine

On catalytic reduction or with lithium aluminium hydride (LiAlH₄) or with nascent hydrogen, alkyl isocyanide yield $2°$ amine whereas cyanide gives $1°$ amine on reduction.

When an organometallic compound (RMgX) reacts with cyanogen chloride (ClCN), the Grignard reagent undergoes nucleophilic addition followed by elimination, leading to the formation of an organo-nitrile (RCN). Hence, the correct option is RCN.

$$\begin{gathered} \underset{1°}{{\mathrm{R}}_1{\mathrm{CH}}_2{\mathrm{NO}}_2}\stackrel{HN{O}_2}{\to }{R}_1-\underset{NOH}{\underset{\left|\right|}{C}}-N{O}_2\stackrel{NaOH}{\to }\underset{\mathrm{Red}}{R_1-\underset{NONa}{\underset{\left|\right|}{C}}-N{O}_2} \\ \underset{2°}{{\mathrm{R}}_2{\mathrm{CHNO}}_2}\stackrel{HN{O}_2}{\to }{R}_2-\underset{NO}{\underset{|}{C}}-N{O}_2\stackrel{NaOH}{\to }\underset{Blue}{R_1-\underset{NO}{\underset{|}{C}}-N{O}_2} \\ \underset{\mathit{3}\mathit{°}}{{\mathit{R}}_{\mathit{3}}{\mathit{CNO}}_{\mathit{2}}}\stackrel{\mathit{H}\mathit{N}{\mathit{O}}_{\mathit{2}}}{\mathit{\to }}No\mathit{ }reaction \end{gathered}$$