Chemistry MCQs for NEET — Practice Questions with Answers

CH₂-CH₂-COOH $\stackrel{{\mathrm{SOCl}}_2}{\to }$CH₃-CH₂-COCl $\underset{∆}{\overset{N{H}_3}{\to }}$CH₃-CH₂-CONH₂ $\underset{{\mathrm{Br}}_2}{\overset{\mathrm{KOH}}{\to }}$CH₃-CH₂-NH₂

A =  ${\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{CHO}$

B = ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{COOH}$

C = ${\mathrm{CH}}_3-\underset{\mathrm{Br}}{\underset{|}{\mathrm{CH}}}-\mathrm{COOH}$

D = ${\mathrm{CH}}_3-\underset{OH}{\underset{|}{\mathrm{CH}}}-\mathrm{COOH}$

CH₃CN  $\stackrel{\mathrm{Na}/{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}}{\to }$ CH₃-CH₂-NH₂  $\stackrel{\mathrm{HNO}2}{\to }$CH₃-CH₂-OH  $\stackrel{{\mathrm{KMnO}}_4,{\mathrm{H}}^{+}}{\to }$ CH₃COOH

The slowest step in the Cannizzaro reaction is the hydride shift. This involves the migration of a hydride ion from the alkoxide anion to the carbonyl carbon, forming an aldehyde and an alcohol.

${\mathrm{CH}}_2=\mathrm{CH}-\mathrm{CH}=\mathrm{O}\to \stackrel{\oplus }{\mathrm{C}}{\mathrm{H}}_2-\mathrm{CH}=\mathrm{CH}-{\mathrm{O}}^{-}\stackrel{\mathrm{HCN}}{\to }\underset{\mathrm{CN}}{\underset{|}{{\mathrm{CH}}_2}}-\mathrm{CH}=\mathrm{CH}-\mathrm{OH}\stackrel{\mathrm{Tautomerisation}}{\to }\underset{\mathrm{CN}}{\underset{|}{{\mathrm{CH}}_2}}-{\mathrm{CH}}_2-\mathrm{CHO}$

Order of reactivity of acid deravative towards nucleophilic substitution is :

CH₃COCl >(CH₃CO)₂O > CH₃COOC₂H_{5 >}CH₃CONH₂

PhCOOH dissolves in aq. NaHCO₃ solution.

CI has more — I and less + M effect.

Maleic acid is a cis-isomer of butenedioic acid, which remains unaffected upon heating. The other options, malonic acid, fumaric acid (trans-isomer), and succinic acid, undergo decarboxylation upon heating, releasing carbon dioxide.

(b) ${\mathrm{PhCOCH}}_3\underset{\mathrm{HCl}}{\overset{{\mathrm{NaNO}}_2}{\to }}\left[{\mathrm{PhCOCH}}_2\mathrm{NO}\right]\to \mathrm{PhCOCH}=\mathrm{NOH}\underset{\mathrm{dehydrating} \mathrm{agent}}{\overset{{\mathrm{Ac}}_2\mathrm{O}}{\to }}\mathrm{PhCOCN}\stackrel{{\mathrm{H}}^{+}/{\mathrm{H}}_2\mathrm{O}}{\to }{\mathrm{PhCOCO}}_2\mathrm{H}$