(i) Define the term functional group. Identify the functional group present in the following:
(ii) What happens when 5% alkaline KMnO 4 solution is added drop by drop to warm ethanol taken in a test-tube? State the role of alkaline KMnO 4 solution in this reaction.
Answer
(i) A functional group is a heteroatom or a group of atoms attached to the carbon chain which gives certain characteristic properties to a compound.
In the compound given above, there is an oxygen atom attached to the carbon atom through a double bond.
So, the functional group is ketone.
In the compound given above, there is an oxygen atom attached to the carbon atom through a double bond and an OH group attached through a single bond to the same carbon atom.
So, the functional group is carboxylic acid .
(ii) Alkaline KMnO 4 is an oxidising agent. On reaction with ethanol, KMnO 4 oxidises it to ethanoic acid and the reaction that takes place is as follows: