NEET Practice Questions (MCQs) with Answers & Solutions

On condensation of two moles of ethyl acetate in the presence of sodium ethoxide, gives ethyl aceto-acetate (ester). This condensation is an example of Claisen condensation because it is possible in that ester which have a-hydrogen atom.

$$\begin{gathered} \mathrm{O} \mathrm{O} \\ \parallel \parallel \\ {\mathrm{CH}}_3-\mathrm{C}-\mathrm{O}-{\mathrm{C}}_2{\mathrm{H}}_5 + \mathrm{H}-{\mathrm{CH}}_2{\mathrm{COOC}}_2{\mathrm{H}}_5 \stackrel{{\mathrm{NaOC}}_2{\mathrm{H}}_5}{\to } {\mathrm{CH}}_3{\mathrm{CCH}}_2{\mathrm{COOC}}_2{\mathrm{H}}_5 + {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH} \end{gathered}$$

(b) When acetamide is heated with aq. NaOH it forms NH₃ gas but ethylamine cannot form NH₃.

 CH₃CONH₂ + H₂O$\stackrel{\mathrm{NaOH}}{\to }$CH₃COONa + NH₃

CH₃CH₂NH₂ + H₂O $\stackrel{\mathrm{NaOH}}{\to }$No reaction

Basically, all Azo dyes are derivatives of aniline.

CH₃CH₂Cl $\stackrel{\mathrm{NaCN}}{\to }$$\underset{\mathrm{X}}{{\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{CN}}$$\stackrel{\mathrm{Ni}/{\mathrm{H}}_2}{\to }$$\underset{\mathrm{Y}}{{\mathrm{CH}}_3-{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{NH}}_2}$$\stackrel{\mathrm{Acetic} \mathrm{anhydride}}{\to }$$\underset{\mathrm{Z}}{{\mathrm{CH}}_3-{\mathrm{CH}}_2-{\mathrm{CH}}_2-{\mathrm{NHCOCH}}_3}$

 CH₃CONH₂ $\stackrel{{\mathrm{P}}_2{\mathrm{O}}_5}{\to }$CH₃CN$\stackrel{4\mathrm{H}}{\to }$CH₃CH₂NH₂

(c) CH₃COOH + NH₃ $\to$CH₃COONH₄$\stackrel{∆}{\to }$CH₃CONH₂$\stackrel{{\mathrm{P}}_2{\mathrm{O}}_5}{\to }$CH₃CN

CH₃CN is ethane nitrile or acetonitrile or methyl cyanide.

Hofmann's method is used to separate primary, secondary and tertiary amines. The compound used is diethyl oxalate for this purpose.

$R{\mathrm{CH}}_2{\mathrm{NO}}_2 \stackrel{\mathrm{HOH}}{\to }R\mathrm{COOH} + {\mathrm{NH}}_2\mathrm{OH}$

The molecular formula C₄H₁₁N represents a primary amine with four carbon atoms. The general formula for primary amines is RNH₂, where R is an alkyl group. There are four possible primary amines with four carbon atoms: CH₃CH₂CH₂CH₂NH₂ (butylamine), CH₃CH₂CH(NH₂)CH₃ (isobutylamine), CH₃CH(NH₂)CH₂CH₃ (sec-butylamine), and (CH₃)₂CHCH₂NH₂ (tert-butylamine).