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Answer the following.
What happens when (write chemical equations): (a) Benzaldehyde is heated with alcoholic . (b)…
What happens when (write chemical equations):
(a) Benzaldehyde is heated with alcoholic $\text{KCN}$.
(b) Formaldehyde is heated with conc. $\text{NaOH}$ solution.
(c) Acetone is treated with hydroxylamine.
Answer
Answer
AIEquations: $2\mathrm{C_{6}H_{5}CHO} \xrightarrow{\text{alc.}\text{ }\text{KCN}\text{,}\text{ }\text{heat}} \mathrm{C_{6}H_{5}CH(OH)COC_{6}H_{5}}$ $2\mathrm{HCHO} + \mathrm{NaOH} \xrightarrow{\text{conc.}\text{ }\text{NaOH}\text{,}\text{ }\text{heat}} \mathrm{CH_{3}OH} + \mathrm{HCOONa}$ $\mathrm{CH_{3}COCH_{3}} + \mathrm{NH_{2}OH} \longrightarrow \mathrm{(CH_{3})_{2}C=NOH} + \mathrm{H_{2}O}$
Products: benzoin, methanol and sodium formate, acetoxime
(a) Benzoin condensation: two molecules of benzaldehyde condense to give benzoin.
(b) Cannizzaro reaction: formaldehyde (no $\alpha$-hydrogen) gives methanol and sodium formate.
(c) Acetone condenses with hydroxylamine to give acetoxime (acetone oxime) and water.
From ISC 2026 Improvement Chemistry Paper 1, question 19(i).