Medicneet Logo
NEET 2025 · ChemistryPrevious Year Question

Which one of the following compounds can exist as cis-trans isomers?

Answer: (B) 1,2-Dimethylcyclohexane. \textbf{Answer:} (b) \textbf{Solution:} Cis-trans (geometrical) isomerism requires two different groups on each of two carbons whose relative spatial arrangement is fixed by a ring or a C=C double bond.

  1. A.1,1-Dimethylcyclopropane
  2. B.1,2-Dimethylcyclohexane✓
  3. C.Pent-1-ene
  4. D.2-Methylhex-2-ene

Correct Answer

(B) 1,2-Dimethylcyclohexane

Solution & Explanation

\textbf{Answer:} (b) \textbf{Solution:} Cis-trans (geometrical) isomerism requires two different groups on each of two carbons whose relative spatial arrangement is fixed by a ring or a C=C double bond. In 1,2-dimethylcyclohexane the two methyls are on adjacent ring carbons and can lie on the same face (cis) or opposite faces (trans). 1,1-Dimethylcyclopropane has both methyls on one carbon (no cis/trans); pent-1-ene has a terminal (two identical H); and in 2-methylhex-2-ene one doubly-bonded carbon bears two identical methyl groups, so neither of these shows cis-trans isomerism.

🎯
43,000+ questions in हिंदी & English · one-tap toggle
Practice NEET 2025 Chemistry — free, with instant solutions
43,000+ NEET questions solved step-by-step, chapter-wise, in the MedicNEET app.
📚Practice all NEET Chemistry PYQs chapter-wise →💡Don't get it? Learn the General Principles Of Organic Chemistry concepts →
← Chemistry Q7Chemistry Q9 →

More NEET PYQ solutions

ChemIdentify the suitable reagent for the following conversion: 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 C6H5-CO-CH2-CH2-CN is treated with (i) CH3MgBr (excess) and then (ii) H3O+.ChemOut of the following complex compounds, which compound will have the minimum conductance in solution?ChemWhich of the following are paramagnetic? A. [NiCl4]^2- B. Ni(CO)4 C. [Ni(CN)4]^2- D. [Ni(H2O)6]^2+ E. Ni(PPh3)4ChemThe correct order of the wavelength of light absorbed by the following complexes is: A. [Co(NH3)6]^3+ B. [Co(CN)6]^3- C. [Cu(H2O)4]^2+ D. [Ti(H2O)6]^3+ChemThe correct order of decreasing basic strength of the given amines is: (N-ethylethanamine = (C2H5)2NH; ethanamine = C2H5NH2; N-methylaniline = C6H5NH(CH3); benzenamine/aniline = C6H5NH2)ChemPredict the major product P in the following sequence of reactions. The starting material is 1-methylcyclopent-1-ene: (i) HBr, benzoyl peroxide; (ii) KCN; (iii) Na(Hg)/C2H5OH P (major). The structures of the options (A)-(D) are shown in the image below:
More: All NEET 2025 Chemistry PYQs · NEET Chemistry PYQs · All NEET PYQs · Previous year papers