NEET 2025 · ChemistryPrevious Year Question
The total number of possible isomers (both structural as well as stereoisomers) of cyclic ethers of molecular formula $\ce{C4H8O}$ is:
- A.10
- B.11✓
- C.6
- D.8
Correct Answer
(B) 11
Solution & Explanation
\textbf{Answer:} (b) \textbf{Solution:} The cyclic ethers of $\ce{C4H8O}$ comprise the four-membered oxetanes (oxetane, 2-methyloxetane, 3-methyloxetane), the five-membered oxolane (tetrahydrofuran) and the three-membered oxiranes bearing alkyl groups (2-ethyloxirane and 2,2- / 2,3-dimethyloxirane). Several of these rings (e.g. 2-methyloxetane, 2-ethyloxirane and 2,3-dimethyloxirane) carry a stereocentre and exist as R/S enantiomers, and 2,3-dimethyloxirane also has cis/trans forms. Summing all constitutional isomers together with their stereoisomers gives 11.
🎯
Practice NEET 2025 Chemistry — free, with instant solutions
10,000+ NEET PYQs solved step-by-step, chapter-wise, in the MedicNEET app.
More NEET PYQ solutions
ChemIdentify the suitable reagent for the following conversion: \ce{C6H5COOCH3 -> C6H5CHO} (methyl benzoate to benzaldehyde)ChemThe correct order of decreasing acidity of the following aliphatic acids isChemThe major product of the following reaction is: 4-oxo-4-phenylbutanenitrile \ce{C6H5-CO-CH2-CH2-CN} is treated with (i) \ce{CH3MgBr} (excess) and then (ii) \ce{H3O+}.ChemOut of the following complex compounds, which compound will have the minimum conductance in solution?ChemWhich of the following are paramagnetic? A. \ce{[NiCl4]^2-} B. \ce{Ni(CO)4} C. \ce{[Ni(CN)4]^2-} D. \ce{[Ni(H2O)6]^2+} E. \ce{Ni(PPh3)4}ChemThe correct order of the wavelength of light absorbed by the following complexes is: A. $\ce{[Co(NH3)6]^3+}$ B. $\ce{[Co(CN)6]^3-}$ C. $\ce{[Cu(H2O)4]^2+}$ D. $\ce{[Ti(H2O)6]^3+}$ChemThe correct order of decreasing basic strength of the given amines is: (N-ethylethanamine $=$ \ce{(C2H5)2NH}; ethanamine $=$ \ce{C2H5NH2}; N-methylaniline $=$ \ce{C6H5NH(CH3)}; benzenamine/aniline $=$ \ce{C6H5NH2})ChemPredict the major product $P$ in the following sequence of reactions. The starting material is 1-methylcyclopent-1-ene: (i) \ce{HBr}, benzoyl peroxide; (ii) \ce{KCN}; (iii) \ce{Na(Hg)}/\ce{C2H5OH} $\rightarrow$ $P$ (major). The structures of the options (A)-(D) are shown in the image below: