Aromaticity, antiaromaticity and Huckel rule

27 questions on Aromaticity, antiaromaticity and Huckel rule from the General Organic Chemistry I: Electronic Effects chapter: 5 NEET level, 10 JEE Main, 12 JEE Advanced. Each one opens with its answer and solution.

• Which of the following is aromatic? NEET level
• According to Huckel's rule, a planar, cyclic, fully conjugated system is aromatic if it contains NEET level
• The number of pi electrons in the cyclopentadienyl anion (cyclopenta-2,4-dien-1-ide) is NEET level
• Which of the following is aromatic? NEET level
• Cyclobutadiene is NEET level
• Which one of the following is aromatic? JEE Main level
• Pyridine is a much stronger base than pyrrole because JEE Main level
• Cyclopenta-1,3-diene is far more acidic than cyclohexa-1,3-diene mainly because JEE Main level
• The cyclopropenyl cation, C3H3+, is JEE Main level
• The number of pi electrons contributed by the oxygen atom of furan to its aromatic sextet is JEE Main level
• Naphthalene is aromatic because it contains JEE Main level
• Which of the following is NOT aromatic because it lacks a continuous cyclic conjugation of p orbitals? JEE Main level
• Assertion (A): The cyclopentadienyl anion is aromatic. Reason (R): It is planar, cyclic, fully conjugated and has 6 pi electrons. JEE Main level
• Benzene mostly undergoes substitution rather than addition because JEE Main level
• Which of the following are antiaromatic? JEE Main level
• Among benzene, pyridine, cyclopentadienyl anion, furan, cyclobutadiene and cyclopenta-1,3-diene, the number of aromatic species is JEE Advanced level
• The correct order of basic strength of piperidine (I), pyridine (II) and pyrrole (III) in water is JEE Advanced level
• In 1H-imidazole (a five-membered ring with two nitrogen atoms at positions 1 and 3, N1 bearing hydrogen), protonation occurs on JEE Advanced level
• Which of the following hydrocarbons readily loses a hydride ion (to a reagent such as Ph3C+) because the resulting cation is aromatic? JEE Advanced level
• The total number of pi electrons in the bicyclic ring system of indole (a benzene ring fused to a pyrrole ring, with N-H), counting the nitrogen lone pair that ... JEE Advanced level
• The total number of pi electrons in anthracene and the value of n in Huckel's 4n+2 relation are respectively JEE Advanced level
• Assertion (A): Pyrrole is a much weaker base than pyridine. Reason (R): In pyrrole the lone pair on nitrogen is part of the aromatic sextet, whereas in pyridine... JEE Advanced level
• Which pair consists of two aromatic species? JEE Advanced level
• Which of the following are aromatic? JEE Advanced level
• Which of the following statements are correct? JEE Advanced level
• Which of the following transformations are favoured because an aromatic ion is produced? JEE Advanced level
• Which of the following statements are correct? JEE Advanced level