The structural formula of an ester is :

$H-\underset{H}{\underset{|}{\stackrel{H}{\stackrel{|}{C}}}}-\stackrel{O}{\stackrel{||}{C}}-O-\underset{H}{\underset{|}{\stackrel{H}{\stackrel{|}{C}}}}-\underset{H}{\underset{|}{\stackrel{H}{\stackrel{|}{C}}}}-H$

Write the formula of the acid and the alcohol from which it is formed.

The structural formula of the ester corresponds to the compound ethyl ethanoate $\left(C{H}_{3}COO{C}_2{H}_5\right)$. Esters are sweet smelling substances which are formed when an alcohol reacts with the carboxylic acid in the presence of concentrated sulphuric acid.

(a) The formula of the ethanoic acid is $C{H}_{3}COOH$.

(b) The formula of the alcohol (ethanol) is $C{H}_3-C{H}_2-OH$.

The chemical equation showing the reactants and the products is as follows:

$C{H}_3-COOH+C{H}_3-C{H}_{2}OH\stackrel{Conc.H_{2}S{O}_4}{\to }C{H}_3-COO-C_2{H}_5+H_{2}O$