Question

Ketones show _________.
(A) Metamerism
(B) Position isomerism
(C) Structural isomerism
(D) Functional group isomerism

Answer 1

Hint: We know that ketones are organic compounds which contain a carbonyl group. In ketones, one carbon atom is attached to an oxygen atom and the other bonds are hydrocarbon radicals. We know that position isomerism, structural isomerism and functional group isomerism are not shown by ketones.

Complete step by step solution:
We know that in ketones, a carbonyl group is attached to two alkyl groups. The alkyl group determines the type of the ketone.
Examples of ketones are as follows:

In dimethyl ketone, two methyl groups are attached to the carbonyl group. In ethyl methyl ketone, one ethyl group and one methyl group is attached to the carbonyl group. In diethyl ketone, two ethyl groups are attached to the carbonyl carbon.
From the structures of the three ketones, dimethyl ketone, ethyl methyl ketone and diethyl ketone we can see that different alkyl groups are attached to the same functional group.
The compounds that have different alkyl groups attached to the same functional group are said to be metamers of each other and the phenomenon is known as metamerism.
Thus, ketones show metamerism.

Thus, the correct option is (A) metamerism.

Note: When the basic carbon skeleton of a molecule remains the same and the important groups are moved around the skeleton it is known as position isomerism. When the molecular formula is the same but the atoms are arranged in a different order it is known as structural isomerism. When the molecular formula is the same but the functional group is different it is known as functional group isomerism.