Question

A compound X is formed by the reaction of a carboxylic acid C₂H₄O₂ and an alcohol in presence of a few drops of H₂SO₄. The alcohol on oxidation with alkaline KMnO₄ followed by acidification gives the same carboxylic acid as used in this reaction. Give the names and structures of

1. carboxylic acid
2. alcohol and
3. the compound X.
   Also write the reaction.

Answer 1

When ethanoic acid (C₂H₄O₂) reacts with absolute ethanol (C₂H₆O) in the presence of an acid catalyst, the ester is formed. So, compound X is ethyl ethanoate. 

\[\ce{CH3COOH + CH3CH2OH -> \underset{Ester}{CH3COOC2H5} + H2O}\]

Ethanol on oxidation with alkaline KMnO₄ gives ethanoic acid.

\[\ce{C2H5OH\overset{Alkaline  KmnO4}{ ->}CH3COOH}\]

1. Ethanol on oxidation with alkaline KMnO₄ gives ethanoic acid.
   \[\begin{array}{cc}
   \ce{H}\phantom{...}\ce{O}\phantom{....}\\
   |\phantom{....}||\phantom{....}\\
   \ce{H - C - C - O - H}\\
   |\phantom{.........}\\
   \ce{H}\phantom{.........}\\
   \end{array}\]
2. Ethanol
   \[\begin{array}{cc}
   \ce{H}\phantom{....}\ce{H}\phantom{....}\\
   |\phantom{....}|\phantom{....}\\
   \ce{H - C - C - O - H}\\
   |\phantom{....}|\phantom{.....}\\
   \ce{H}\phantom{...}\ce{H}\phantom{.....}\\
   \end{array}\]
3. Compound x is ethyl ethanoate (ester).
   \[\begin{array}{cc}
   \phantom{.........}\ce{H}\phantom{...}\ce{O}\phantom{.......}\ce{H}\phantom{...}\ce{H}\phantom{.........}\\
   |\phantom{....}||\phantom{........}|\phantom{....}|\\
   \ce{H - C - C - O - C - C - H}\\
   \phantom{.}|\phantom{.............}|\phantom{....}|\phantom{.}\\
   \phantom{.}\ce{H}\phantom{............}\ce{H}\phantom{...}\ce{H}\phantom{.}
   \end{array}\]