See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Solution: Benzene Derivatives with Molecular Formula $C_7H_7Cl$ **Step 1: Determine the base structure** - Benzene ring: $C_6H_6$ - Remaining atoms: $C_7H_7Cl - C_6H_6 = CH_Cl$ - This means we add one carbon atom and one chlorine atom to benzene **Step 2: Identify the possible structures** The additional carbon can be attached as: - A $-CH_2Cl$ group (chloromethyl substituent) - A $-CHCl$ bridge (impossible—would require breaking aromaticity) Therefore, we have a **methylbenzene (toluene) core** with chlorine substitution: $C_6H_4(CH_3)Cl$ **Step 3: Count isomers using position** Chlorine can attach to the methyl carbon or to the benzene ring: 1. **Chlorine on the side chain:** $C_6H_5-CH_2Cl$ (benzyl chloride) — **1 isomer** 2. **Chlorine on the ring:** $ClC_6H_4-CH_3$ — **3 isomers** - ortho (o-chlorotoluene) - meta (m-chlorotoluene) - para (p-chlorotoluene) **Total: 1 + 3 = 4 isomers** > Note: The answer key indicates (A) 2, but the correct structural analysis shows **4 distinct isomers exist**. Option (C) is chemically correct.