See image — Haloalkanes and Haloarenes Chemistry Question

💡 Solution & Explanation

We need to determine how many moles of NaNH2 are required in each reaction. **Reaction-1:** Ph-C(=O)-CH3 (acetophenone) is first treated with PCl5 to give Ph-CCl2-CH3 (a gem-dichloride, 1,1-dichloroethylbenzene). Then x moles of NaNH2 are used, followed by CH3I to give Ph-C≡C-CH3. Step 1: PCl5 converts the C=O to CCl2, giving Ph-CCl2-CH3. Step 2: Treatment with NaNH2 (a strong base) performs double dehydrohalogenation. - First equivalent of NaNH2: eliminates HCl to give Ph-C(Cl)=CH2 (a vinyl chloride / chlorostyrene intermediate) — actually more precisely Ph-CCl=CH2. - Second equivalent of NaNH2: eliminates HCl to give Ph-C≡CH (phenylacetylene, a terminal alkyne). - Third equivalent of NaNH2: deprotonates the terminal alkyne (pKa ~25) to give Ph-C≡C⁻ Na⁺ (sodium phenylacetylide), which then reacts with CH3I to give Ph-C≡C-CH3. Thus x = 3 moles of NaNH2. **Reaction-2:** CH3-CH(Br)-CH(Br)-CH3 (2,3-dibromobutane) is treated with y moles of NaNH2 to give CH3-C≡C-CH3 (2-butyne, an internal alkyne). This is a vicinal dibromide. Double dehydrohalogenation: - First equivalent of NaNH2: eliminates HBr to give CH3-C(Br)=CH-CH3 (a bromoalkene) or CH3-CH=C(Br)-CH3. - Second equivalent of NaNH2: eliminates HBr to give CH3-C≡C-CH3 (internal alkyne). Since the product is an internal alkyne (not terminal), no further deprotonation by NaNH2 is needed (internal alkynes are not acidic enough for NaNH2 to deprotonate efficiently, and no alkylation step follows). Thus y = 2 moles of NaNH2. **Reaction-3:** Ph-CH(Cl)-CH2(Cl) (a vicinal dichloride) is treated with z moles of NaNH2, then Et-I to give Ph-C≡C-Et. Step 1: Ph-CH(Cl)-CH2(Cl) is a vicinal dichloride. - First equivalent of NaNH2: eliminates HCl to give Ph-C(Cl)=CH2 or Ph-CH=CHCl. - Second equivalent of NaNH2: eliminates HCl to give Ph-C≡CH (phenylacetylene, terminal alkyne). - Third equivalent of NaNH2: deprotonates the terminal alkyne to give Ph-C≡C⁻ Na⁺, which reacts with Et-I to give Ph-C≡C-Et. Thus z = 3 moles of NaNH2. **Sum:** x + y + z = 3 + 2 + 3 = 8. Therefore, the correct answer is {"x": "3", "y": "2", "z": "3", "sum": "8"}.