Which of the following compounds is aromatic?

• A. Cyclobutadiene ($C_4{H}_4$)
• B. Cyclohexane ($C_6{H}_{12}$)
• C. 1,3-Butadiene ($C_4{H}_6$)
• D. Benzene ($C_6{H}_6$)

Answer: (D)

Verified step by step guidance

1. Recall the criteria for aromaticity: a compound must be cyclic, planar, fully conjugated (p orbitals at every atom in the ring), and follow Hückel's rule, which states it must have (4n + 2) π electrons, where n is a non-negative integer (0, 1, 2, ...).
2. Analyze each compound to check if it meets these criteria. For example, determine if the compound is cyclic and planar, and count the number of π electrons involved in conjugation.
3. For Cyclobutadiene (C\_4H\_4), identify the number of π electrons and check if it fits Hückel's rule. Also consider its planarity and conjugation.
4. For Cyclohexane (C\_6H\_12), note that it is a saturated ring with only single bonds, so it lacks π electrons and conjugation, thus it cannot be aromatic.
5. For 1,3-Butadiene (C\_4H\_6), recognize that it is not cyclic, so it cannot be aromatic despite having conjugated double bonds. Finally, for Benzene (C\_6H\_6), verify that it is cyclic, planar, fully conjugated, and has 6 π electrons, which satisfies Hückel's rule, confirming its aromaticity.