Compounds B, C, and D are aromatic. Aromatic compounds must follow Huckel’s rule (\(4n + 2\) electrons) and have a planar, conjugated structure. Compound A is not aromatic as it does not satisfy these criteria.
List I (Molecule) | List II (Number and types of bond/s between two carbon atoms) | ||
A. | ethane | I. | one σ-bond and two π-bonds |
B. | ethene | II. | two π-bonds |
C. | carbon molecule, C2 | III. | one σ-bonds |
D. | ethyne | IV. | one σ-bond and one π-bond |