The isomerism which exists between CH3CHCI2 and CH2CI. CH2CI is A. chain isomerism B. functional group isomerism C. positional isomerism D. metamerism

The correct answer is: C. positional isomerism

Positional isomerism is a type of structural isomerism in which two or more compounds have the same molecular formula but differ in the position of a substituent group on the carbon chain.

In the case of CH3CHCI2 and CH2CI, both compounds have the molecular formula C2H4Cl2. However, in CH3CHCI2, the chlorine atom is attached to the second carbon atom in the chain, while in CH2CI, the chlorine atom is attached to the first carbon atom in the chain.

Therefore, CH3CHCI2 and CH2CI are positional isomers.

Here is a brief explanation of each option:

• Chain isomerism is a type of structural isomerism in which two or more compounds have the same molecular formula but different carbon skeletons. For example, butane (C4H10) and 2-methylpropane (C4H10) are chain isomers.
• Functional group isomerism is a type of structural isomerism in which two or more compounds have the same molecular formula but different functional groups. For example, ethanol (C2H6O) and dimethyl ether (C2H6O) are functional group isomers.
• Metamerism is a type of structural isomerism in which two or more compounds have the same molecular formula and the same functional group but different alkyl groups attached to the functional group. For example, 1-butanol (C4H10O) and 2-butanol (C4H10O) are metamers.