See image — Hydrocarbons Chemistry Question

💡 Solution & Explanation

Concept: For an alkane to give only one monohalogenated product, all hydrogen atoms in the molecule must be equivalent (homotopic). We analyze each option: 2-methyl butane (isopentane, C5H12): Structure is CH3-CH(CH3)-CH2-CH3. It has primary H atoms on three different methyl groups (but not all equivalent), secondary H on C3, and tertiary H on C2. Multiple types of H atoms exist, so multiple monohalogenated products form. This option fails. 2,2-dimethyl propane (neopentane, C5H12): Structure is C(CH3)4 — a central carbon with four identical methyl groups. All 12 hydrogen atoms are equivalent (all are primary H on equivalent methyl groups). Therefore, halogenation gives only one monohalogenated product: 1-halo-2,2-dimethylpropane. This option works. Cyclopentane (C5H10): Structure is a ring of five CH2 groups. All 10 hydrogen atoms are equivalent by symmetry (all are secondary H on equivalent CH2 groups in the ring). Therefore, halogenation gives only one monohalogenated product: halocyclopentane. This option works. Since both (b) 2,2-dimethyl propane and (c) cyclopentane give only one monohalogenated product, the correct answer is option (d) both (b) and (c). Therefore, the correct answer is D.