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

In the given reaction, an asymmetric carbon atom is generated when HCN adds to acetaldehyde (CH3CHO). The resulting product, 2-hydroxypropanoic acid (CH3CH(OH)COOH), exists as a racemic mixture containing equal amounts (50%) of the D and L isomers.

CH₃COCH₃ $\stackrel{{\mathrm{LiAlH}}_4}{\to }$CH₃CHOHCH₃

This will give iodoform test.

Dihydrogen sodium phosphate (NaH₂PO₄) does not react with aldehydes and ketones because NaH₂PO₄ does not have any lone pair of electron on phosphorus atom, so it cannot act as a nucleophile.

 H₂C₂O₄ $\underset{∆}{\overset{{\mathrm{H}}_2{\mathrm{SO}}_4}{\to }}$ H₂O +CO + CO₂

When benzene sulfonic acid is treated with phosphorus pentoxide (P2O5), the sulfonic acid group (-SO3H) is dehydrated to form the corresponding benzene sulfonic acid anhydride or benzenesulfonyl anhydride.

(b) Crotonaldehyde is CH₃.CH=CH.CHO.

The IUPAC name for CH3COCH(CH3)2 is 3-methyl-2-butanone. The longest carbon chain has 4 carbon atoms, with a ketone (CO) group at the 2nd position and a methyl (CH3) group at the 3rd position.

 ${}_{\mathrm{H}}{}^{{\mathrm{CH}}_3}>\mathrm{C}=\mathrm{O} \stackrel{\mathrm{HCN}}{\to }{}_{\mathrm{H}}{}^{{\mathrm{CH}}_3}>\mathrm{C}{<}_{\mathrm{CN}}^{\mathrm{OH}}\stackrel{\mathrm{HOH}}{\to }{\mathrm{CH}}_3\mathrm{CH}\left(\mathrm{OH}\right)\mathrm{COOH}$

                                                           (Lactic acid)

(a) Higher is K_a or lower is pK_a, stronger is acid.