Question

Esters are sweet-smelling substances and are used in making perfumes. Suggest some activity and the reaction involved for the preparation of an ester with well labeled diagram.

Answer 1

Esters are commonly formed by the reaction of an acid and an alcohol. The following activity can be performed for the preparation of an ester:

Take 1 ml ethanol and 1 ml glacial acetic acid in a test tube. Put some drops of conc. sulphuric acid in the test tube. Warm this in a water bath for few minutes ( at least 5 mins). Pour this into a beaker containing 20-50 ml of water and smell the mixture. If it smells sweet, that means, ester has been formed. Esters are sweet-smelling substances which are used in making perfumes and as flavouring agents. 

\[\begin{array}{cc}
\ce{\underset{(Ethanoic acid)}{CH3 - COOH} + \underset{(Ethanal)}{CH3 - CH2OH} \overset{Acid}{<=>} CH3 - C - \underset{(Easter)}{O - CH2} - CH3 + H2O}
\end{array}\]