FREE IGNOU BCHCT 131 SOLVED ASSIGNMENT 2023

Question 11: Explain Position isomerism, Functional group isomerism, and Chiral centre.

(i) Position Isomerism: This occurs when the position of a functional group or substituent in a molecule changes. For example, consider isomers of butanol: n-butanol and isobutanol. They have the same molecular formula (C₄H₁₀O) but differ in the position of the -OH group.

(ii) Functional Group Isomerism: This occurs when molecules with the same molecular formula have different functional groups. For example, ethanol (CH₃CH₂OH) and dimethyl ether (CH₃OCH₃) are functional group isomers.

(iii) Chiral Centre: A chiral center is an atom, usually a carbon atom, that is bonded to four different substituents. Molecules with chiral centers are chiral and exist as enantiomers, non-superimposable mirror images. For example, the carbon atom in a tetrahedral configuration in chiral molecules like L-alanine or D-glucose is a chiral center.