See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Solution: Identifying Isomer Pairs **Key Concept:** Isomers have the same molecular formula but different structural arrangements. --- ## **Option (A): $(CH_3)_2CHOC_2H_5$ ; $CH_3(CH_2)_2OC_2H_5$** **Molecular formula for both:** - First compound: $C_6H_{14}O$ - Second compound: $C_6H_{14}O$ ✓ Both are structural isomers (different carbon skeletons with same functional group). --- ## **Option (B): $CH_3CH_2NO_2$ ; $CH_2(NH_2)COOH$** **Molecular formula for both:** - First compound: $C_2H_5NO_2$ - Second compound: $CH_2(NH_2)COOH = C_2H_5NO_2$ ✓ These are functional group isomers (nitro compound vs. amino acid). --- ## **Option (C): $(CH_3)_2CH(CH_2)_2CH_3$ ; $CH_3(CH_2)_2CH(CH_3)_2$** **Molecular formula for both:** - First compound: $C_6H_{14}$ - Second compound: $C_6H_{14}$ ✓ However, these represent the **same compound** (3-methylpentane), just written differently—not isomers. ✗ --- ## **Option (D): $CH_3CH_2CO_2H$ ; $CH_3CO_2CH_3$** **Molecular formula for both:** - First compound: $C_3H_6O_2$ - Second compound: $C_3H_6O_2$ ✓ These are functional group isomers (carboxylic acid vs. ester). --- **Answer: A, B, D are correct pairs of isomers.**