Answer :
Answer : The correct option is, (4) an ester.
Explanation :
As we know that an organic acid is an organic compound that has the properties of an acid. For example : Acetic acid.
And the alcohol is an organic compound that contains one or more hydroxyl groups attached to a carbon atom. Fro example : Ethanol.
When an organic acid react with an alcohol the it produces an ester.
For example : when an organic acid (acetic acid) react with an alcohol (ethanol) to gives an ester (methoxyethane).
The balanced chemical reaction will be,
[tex]CH_3COOH+CH_3OH\rightarrow CH_3C-O-O-CH_3+H_2O[/tex]
Hence, the reaction between an organic acid and an alcohol produces an ester.