Phản ứng nào dưới đây không thể hiện tính oxi hóa - khử của hợp chất aldehyde?
\(\mathrm{CH}_3 \mathrm{CH}=\mathrm{O}+2[\mathrm{H}] \rightarrow \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{OH}\).
\(\mathrm{CH}_3 \mathrm{CHO}+\mathrm{Br}_2+\mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{CH}_3 \mathrm{COOH}+\mathrm{HBr}\).
\(\mathrm{CH}_3 \mathrm{CHO}+2\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right] \mathrm{OH} \xrightarrow{t^o} \mathrm{CH}_3 \mathrm{COONH}_4+2 \mathrm{Ag}+3 \mathrm{NH}_3+\mathrm{H}_2 \mathrm{O}\).
\(\mathrm{CH}_3 \mathrm{CHO}+\mathrm{HCN} \rightarrow \mathrm{CH}_3 \mathrm{CH}(\mathrm{OH}) \mathrm{CN}\).
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Phương pháp giải
Tính chất của aldehyde.
Lời giải
Phản ứng không thể hiện tính oxi hóa - khử của aldehyde là CH3CHO + HCN → CH3CH(OH)CN, vì phản ứng này là phản ứng cộng.
Chọn đáp án D.
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