Question 10 - Past Year - 3 Mark Questions - Chapter 4 Class 10 - Carbon and its Compounds

(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: