Chemistry MCQs for NEET — Practice Questions with Answers

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).

(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<$1°<3°<2°$

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