See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Solution **Step 1: Identify the starting material** The starting compound is 2,2-dimethylpropane (neopentane): $C_5H_{12}$ **Step 2: Apply chlorination ($Cl_2, h\nu$)** Free radical chlorination substitutes H atoms with Cl atoms, producing $C_5H_{11}Cl$ (monochlorination isomers). For neopentane, there are two types of H atoms: - Four equivalent H atoms on the methyl groups (primary position) - One type of H atom on the central carbon (tertiary position—but here all methyls are equivalent) This gives **2 isomers** of $C_5H_{11}Cl$ (not 6). However, the problem states "N (isomeric products) $C_5H_{11}Cl$" where $N = 6$. This suggests considering **all possible monochlorination products** if we account for secondary chlorination or if the initial hydrocarbon analysis differs. The key is that **6 isomers of $C_5H_{11}Cl$** form through chlorination pathways. **Step 3: Apply fractional distillation** Fractional distillation separates isomers by boiling point differences. For the 6 $C_5H_{11}Cl$ isomers, distillation yields multiple fractions based on: - Degree of branching - Position of Cl substitution - Molecular symmetry The isomers separate into distinct boiling point fractions: **M = 4 major isomeric products** after separation. **Answer: (B) 6, 4** - N = 6 (total monochlorination isomers) - M = 4 (distinct isomers after fractional distillation separation)