Question

Assertion: Metamers can also be chain or position isomers:
Reason: The term tautomerism was introduced to explain the reactivity of a substance according to two possible structures.
A.Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B.Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C.Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
D.Both Assertion and Reason are incorrect.

Answer 1

Hint: We know that metamerism occurs among the members of the same homologous family. Sometimes metamers are also called position isomers. The compound which exhibits metamerism has the same molecular weight but the difference in chemical properties.

Complete answer: We have come across the concepts of organic chemistry in the chapters that deal with the stereochemistry that tells us about the arrangement of atoms in a molecule in space. Stereochemistry is the part of organic chemistry which deals with the study of how molecules are affected by the arrangement of their atoms in space. The phenomenon of existence with the same molecular formula of two or more compounds but different properties is known as isomerism and which compounds exhibit this phenomenon is called isomers. This isomerism is observed in compounds having the same molecular formula but different alkyl chains on either side of the functional group of the molecule. For example, diethyl ether and methyl propyl ethers, ethoxyethane and methoxy propane, pentanone represent a pair of metamers. If functional group carbon is part of the principal chain then metamers are also positional isomers and Actually metamerism comes under positional isomerism. It's like metamerism is a subset of positional isomerism.
When a compound has a functional group as a part of its chain then we call positional isomerism as metamerism to specify that the functional group is a part of the chain. and the reason The term tautomerism was introduced to explain the reactivity of a substance according to two possible structures is also true but not the correct explanation for the assertion.
Therefore, the correct answer is option B.

Note:
Remember that the hydrocarbons show conformational isomerism by alkanes due to carbon-carbon rotation along with sigma bonds. Metamerism is a type of chain or position isomerism observed with same functional group and different alkyl groups attached to hetero atom.