Benzene - structure, resonance and aromaticity — NEET & JEE Questions

Question 1 · difficulty L1 · recall

Benzene contains how many carbon atoms in its ring?

• A. 6
• B. 4
• C. 5
• D. 8

Question 2 · difficulty L2 · understanding

All carbon-carbon bonds in benzene have the same length because

• A. pi electrons are delocalised around the ring
• B. benzene contains three isolated double bonds
• C. all carbons are sp3 hybridised
• D. resonance makes alternate bonds fixed

Question 3 · difficulty L2 · understanding

Each carbon atom in benzene is approximately

• A. sp2 hybridised
• B. sp3 hybridised
• C. sp hybridised
• D. unhybridised

Question 4 · difficulty L2 · understanding

Benzene is aromatic because it is cyclic, planar, conjugated and contains

• A. 6 pi electrons satisfying Hückel's $4n+2$ rule
• B. 4 pi electrons satisfying $4n$
• C. 8 pi electrons
• D. no pi electrons

Question 5 · difficulty L3 · application

How many pi electrons are present in benzene?

• A. 6
• B. 3
• C. 12
• D. 2

Question 6 · difficulty L3 · application

Which statement best describes the resonance hybrid of benzene?

• A. It is more stable than any one Kekulé contributor and has equivalent C-C bonds
• B. It rapidly alternates between two real structures
• C. It contains three permanent single and three permanent double bonds
• D. It is non-planar

Question 7 · difficulty L3 · application

The C-C bond length in benzene is expected to be

• A. intermediate between typical single and double C-C bonds
• B. equal to a pure single bond only
• C. equal to a pure double bond only
• D. alternating long and short exactly

Question 8 · difficulty L3 · application

Which property is a direct consequence of aromatic stabilisation in benzene?

• A. It prefers substitution over addition under many conditions
• B. It readily undergoes addition like a normal alkene
• C. It is highly unstable
• D. It has no pi system

Question 9 · difficulty L4 · application

A cyclic planar conjugated molecule has 6 pi electrons. Which rule supports aromaticity?

• A. Hückel's $4n+2$ rule with n = 1
• B. The octet rule alone
• C. The $4n$ antiaromatic rule with n = 1.5
• D. Boyle's law

Question 10 · difficulty L4 · application

Why is the heat of hydrogenation of benzene less exothermic than expected for three isolated C=C bonds?

• A. Benzene is stabilised by aromatic delocalisation
• B. Benzene has no carbon-carbon bonds
• C. Hydrogen cannot react with benzene
• D. Each benzene carbon is sp3 hybridised