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

(b) In (a) t-alcohol, in (c) initially s-alcohol converting to ether. In (d) p-alcohol

(d) pK_a for (a) , (b), (c) and (d) are 4.17, 4.09, 3.49 and 3.43 respectively.

Ethanal (acetaldehyde) reacts with HCN to form an addition product, which upon hydrolysis forms lactic acid (2-hydroxypropanoic acid). Lactic acid exhibits optical isomerism due to the presence of a chiral carbon atom.

C₆H₅CHO+HCHO$\stackrel{\mathrm{NaOH}(\mathrm{conc}.) }{\to }$C₆H₅CH₂OH+HCOONa

                                              Benzyl alcohol      Sod. Formate

Phenolphthalein is produced by the condensation reaction between phthalic anhydride and phenol in the presence of conc. H2SO4. Phenol acts as a nucleophile and attacks the carbonyl carbon of the anhydride.

Aldehyde is more reactive than ketone towards nucleophilic addition

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