Question

A compounds X is fromed by the reaction of a carboxylic acid `C_(2)H_(4)O_(2)` and an alcohol in the presence of a few drops of `H_(2)SO_(4)`. The alcohol on oxidation with alkalne `KMnO_(4)` followed by acidification gives the same carboxylic as used in this reaction. Give the names and structures of (a) carboxylic acid, (b) alcohol and (c ) the compound X. Also write the reaction.

Answer 1

(a) Carboxylic acid having molecular formula `C_(2)H_(4)O_(2)` is (acetic acid or ethanoic acid. Its structure is `CH_(3)-underset(O)underset(||)C-OH`
(b) Since, an alcohol which oxidation with alkaline `KMnO_(4)` followed by acidification gives ethanoic acid. Therefore, it must be ethanol. Its structure is `CH_(3)CH_(2)-OH`.
`CH_(3)CH_(2)OHunderset((ii)"Dil."H_(2)SO_(4))overset((i)"Alk."KMnO_(4))(to)CH_(3)-underset("Ethanoic acid")overset(O)overset(||)C-OH`
(c ) Since compound X is formed by the reaction of ethanoic acid with ethanol in presence of a few drops of conc. `H_(2)SO_(4)`. Therefore, compound X must be an ester, i.e., ethyl sthanoate. Its structure is `CH_(3)-underset(O)underset(||)C-O-C_(2)H_(5)`.
The reaction is
`underset("Ethanoic acid")(CH_(3)COOH)+underset("Ethanol")(C_(2)H_(5))OHoverset(Conc.H_(2)SO_(4))(to)underset("Ethyl ethanoate" ("X-an ester"))(CH_(3)COOC_(2)H_(5)+H_(2)O)`