Aldehyde ketones & carboxylic Acid MCQs for NEET — Chemistry Questions with Answers

Clemmensen reduction of a ketone is carried out in the presence of zinc-mercury amalgam (Zn-Hg) and hydrochloric acid (HCl). This reducing mixture converts the carbonyl group of the ketone into a methylene group, effectively reducing the ketone to an alkane.

The Cannizzaro reaction involves the disproportionation of a non-enolizable aldehyde, forming an alcohol and a carboxylate salt. It does not result in the formation of a carbon-carbon bond.

$$\begin{gathered} >\mathrm{C}=\mathrm{O}+\mathrm{HCN} \stackrel{}{\to } >\mathrm{C}<\begin{array}{c}\mathrm{OH}\\ \mathrm{CN}\end{array}\stackrel{{\mathrm{H}}_2\mathrm{O}}{\to } >\mathrm{C}< \begin{array}{c}\mathrm{OH}\\ \mathrm{COOH}\end{array} \left(\mathrm{It} \mathrm{is} \mathrm{\alpha }-\mathrm{hydroxy} \mathrm{acid}\right) \\ \mathrm{If} \mathrm{it} \mathrm{is} \mathrm{racemic} \mathrm{mixture}, \mathrm{therefore} \mathrm{such} \text{'}\mathrm{c}\text{'} \mathrm{atom} \mathrm{must} \mathrm{be} \mathrm{asymmetric} \mathrm{carbon} \mathrm{atom}. \\ \begin{array}{c}{\mathrm{CH}}_3\\ \mathrm{H}\end{array}>\mathrm{C}=\mathrm{O}+\mathrm{HCN} \stackrel{}{\to } \begin{array}{c}{\mathrm{CH}}_3\\ \mathrm{H}\end{array}>\mathrm{C}<\begin{array}{c}\mathrm{OH}\\ \mathrm{CN}\end{array} \stackrel{{\mathrm{H}}_2\mathrm{O}}{\to }\begin{array}{c}{\mathrm{CH}}_3\\ \mathrm{H}-\mathrm{C}-\mathrm{OH}\\ \begin{array}{c}\mathrm{COOH}\\ \mathrm{d}-\end{array}\end{array}+\begin{array}{c}{\mathrm{CH}}_3\\ \mathrm{HO}-\mathrm{C}-\mathrm{H}\\ \begin{array}{c}\mathrm{COOH}\\ \mathrm{I}-\end{array}\end{array} \\ \mathrm{Acetaldehyde} \mathrm{Racemic} \mathrm{mixture} \\ \begin{array}{c}{\mathrm{CH}}_3\\ {\mathrm{CH}}_3\end{array}>\mathrm{C}=\mathrm{O}+\mathrm{HCN} \to \begin{array}{c}{\mathrm{CH}}_3\\ {\mathrm{CH}}_3\end{array}>\mathrm{C}<\begin{array}{c}\mathrm{OH}\\ \mathrm{CN}\end{array}\stackrel{{\mathrm{H}}_2\mathrm{O}}{\to } \begin{array}{c}{\mathrm{CH}}_3\\ {\mathrm{CH}}_3\end{array}>\mathrm{C}< \begin{array}{c}\mathrm{OH}\\ \mathrm{COOH}\end{array} \\ \mathrm{Acetone} \mathrm{It} \mathrm{is} \mathrm{not} \mathrm{optical} \mathrm{active} \\ \begin{array}{c}{\mathrm{C}}_2{\mathrm{H}}_5\\ {\mathrm{C}}_2{\mathrm{H}}_5\end{array}>\mathrm{C}=\mathrm{O}+\mathrm{HCN} \stackrel{}{\to } \begin{array}{c}{\mathrm{C}}_2{\mathrm{H}}_5\\ {\mathrm{C}}_2{\mathrm{H}}_5\end{array}>\mathrm{C}< \begin{array}{c}\mathrm{OH}\\ \mathrm{CN}\end{array}\stackrel{{\mathrm{H}}_2\mathrm{O}}{\to }\begin{array}{c}{\mathrm{C}}_2{\mathrm{H}}_5\\ {\mathrm{C}}_2{\mathrm{H}}_5\end{array}>\mathrm{C}< \mathrm{COOH} \\ \mathrm{Diethyl} \mathrm{ketone} \mathrm{It} \mathrm{is} \mathrm{not} \mathrm{optical} \mathrm{active} \\ \begin{array}{c}\mathrm{H}\\ \mathrm{H}\end{array}>\mathrm{C}=\mathrm{O}+\mathrm{HCN} \stackrel{}{\to } \begin{array}{c}\mathrm{H}\\ \mathrm{H}\end{array}>\mathrm{C}<\begin{array}{c}\mathrm{OH}\\ \mathrm{CN}\end{array} \stackrel{{\mathrm{H}}_2\mathrm{O}}{\to } \begin{array}{c}\mathrm{H}\\ \mathrm{H}\end{array}>\mathrm{C}<\begin{array}{c}\mathrm{OH}\\ \mathrm{COOH}\end{array} \\ \mathrm{Formaldehyde} \mathrm{It} \mathrm{is} \mathrm{not} \mathrm{optical} \mathrm{active} \end{gathered}$$

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.

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

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

Substitution of -OH group from a substrate can be easily made by PCl₅

The formation of cyanohydrin from a ketone is an example of a nucleophilic addition reaction. In this reaction, the cyanide ion (CN⁻) acts as a nucleophile and attacks the electrophilic carbonyl carbon of the ketone, forming a cyanohydrin product.

Among the given options, 1-butyne has the minimum pH value as the triple bond is more acidic than double and single bonds due to the greater s-character of the sp-hybridized carbon atom, making the hydrogen more acidic.

 $Reactivity \alpha -I power of the group$

 $Reactivity \alpha -I power$