Which of following is aromatic hydrocarbon?1. A. Anthracene2. B. Furan3. C. Pyridine4. D. All of these

To determine which of the options is an aromatic hydrocarbon, we need to understand the characteristics of aromatic compounds:

1. Definition of Aromatic Compounds: Aromatic compounds are cyclic, planar molecules that follow Huckel's rule, which states that a molecule must have $4n + 2$ π electrons (where n is a non-negative integer) in a conjugated π system to be considered aromatic.

2. Analyzing Each Option:

   • A. Anthracene: Anthracene is a polycyclic aromatic hydrocarbon with a structure consisting of three fused benzene rings. It has a total of 14 π electrons, which satisfies Huckel's rule ($n = 3$).
   • B. Furan: Furan is a five-membered ring containing one oxygen atom. It is not classified as an aromatic hydrocarbon because it does not meet the criteria; it has 6 π electrons, but the presence of an electronegative atom like oxygen affects the aromatic stability.
   • C. Pyridine: Pyridine is a six-membered aromatic ring containing one nitrogen atom. It has 6 π electrons (contributed by the 5 carbon atoms), thus qualifying as an aromatic compound.
   • D. All of these: This option implies that all the listed compounds are aromatic hydrocarbons.

Conclusion:

• Anthracene and pyridine are aromatic, but furan is not an aromatic hydrocarbon. Thus, the correct answer is not "All of these."

Final Answer:

The correct answer is A. Anthracene and C. Pyridine (not D. All of these).