The left side part of the formula of ana ester (containing the CO part ) is derived from the acid and the right side part of and easter is derived from the alcohol .So in the ester `C_(3)H_(7)COOC_(2)H_(5)`, the acid will be `C_(3)H_(7)COOH` and the alcohol will be `HOC_(2)H_(5)` which is written more conveniently as `C_(2)H_(5)OH` Thus
(i) The acid present in the ester `C_(3)H_(7)COOC_(2)H_(5) "is" C_(3)H_(7)COOH` which is butanoic acid .
(ii) The reaction of butanoic aid and ethanol to from this ester can be represented as:
