CBSE 2022 · Region 4 · Set 2 · Q8 · 3 marks
A compound 'A' $\displaystyle \left(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}\right)$ on oxidation gives 'B' $\displaystyle \left(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}\right)$. 'A' undergoes Iodoform reaction to give yellow precipitate and reacts with HCN to form the compound 'C'. 'C' on hydrolysis gives $\displaystyle 2$ -hydroxypropanoic acid. Identify the compounds 'A', 'B' and 'C'. Write down equations for the reactions involved.
Marking-scheme solution
A = Acetaldehyde / $\displaystyle \mathrm{CH_3CHO}$
B = Ethanoic acid / $\displaystyle \mathrm{CH_3COOH}$
C = Acetaldehyde cyanohydrin / $\displaystyle \mathrm{CH_3CH(OH)CN}$$\displaystyle \mathrm{CH_3CHO}$ (A) $\displaystyle \xrightarrow{[\mathrm{O}]}$ $\displaystyle \mathrm{CH_3COOH}$ (B)$\displaystyle \mathrm{CH_3CHO}$ (A) $\displaystyle \xrightarrow{\mathrm{I_2\ NaOH}}$ $\displaystyle \mathrm{CHI_3}$ (Yellow ppt)$\displaystyle \mathrm{CH_3CHO}$ (A) $\displaystyle \xrightarrow{\mathrm{HCN}}$ (C) (C) $\displaystyle \xrightarrow{\mathrm{H_2O/H^+}}$
Aldehydes, Ketones and Carboxylic AcidsChemical Reactions of Aldehydes, Ketones and Carboxylic AcidsAnalyseshort_answermedium
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CBSE Class 12 Chemistry past-paper question from the 2022board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.