How will you convert ethanal into the ...

NCERT Class XII Chemistry
Chapter - Aldehydes, Ketones and Carboxylic Acids
Questions with Solutions

Question : 8 of 28

Marks: +1, -0

How will you convert ethanal into the following compounds?

(i) Butane-1,3-diol (ii) But-2-enal (iii) But-2-enoic acid

Solution:

(i) \underset{\text{Ethanal}}{2\mathrm{CH_3CHO}} \xrightarrow[\text{Aldol condensation}]{\text{Dil. NaOH}} \underset{\text{3-Hydroxybutanal}}{\overset{4}{\mathrm{C}}\overset{3}{\mathrm{H_3C}}\overset{2}{\mathrm{HOHC}}\overset{1}{\mathrm{H_2C}}\mathrm{HO}} \xrightarrow[\text{(Reduction)}]{\mathrm{NaBH_4}} \underset{\text{Butane-1,3-diol}}{\overset{4}{\mathrm{C}}\mathrm{H_3OH}-\overset{3}{\mathrm{C}}\mathrm{HOH}-\overset{2}{\mathrm{C}}\overset{1}{\mathrm{H_2C}}\mathrm{H_2OH}}

(ii) \underset{\text{Ethanal}}{2\mathrm{CH_3CHO}} \xrightarrow[(ii)\,\mathrm{H}^{+},\,\Delta]{(i)\,\text{dil. NaOH}} \underset{\text{But-2-enal}}{\mathrm{CH_3CH=CHCHO}}

2\mathrm{CH_3CHO} \xrightarrow[\Delta]{\text{aq. NaOH}} \mathrm{CH_3CH=CHCHO} \xrightarrow[\text{Tollens' reagent}]{[\mathrm{Ag(NH_3)}]^{+}\mathrm{OH}^{+}} \underset{\text{But-2-enoic acid}}{\mathrm{CH_3CH=CHCO_2H}}

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