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QJEEM21Ch22c3: JEE Main 2021 Chemistry - Class 11 JEEM21Ch22c3 Solution: Which one of the following compounds is aromatic in nature?

Which one of the following compounds is aromatic in nature?

Multiple Choice Options

  • A https://ik.imagekit.io/novatra/photos/9f79542d3853106c78c92dd9de79fe157768369e059e3165a3836a8053ce0901.webp
  • B https://ik.imagekit.io/novatra/photos/e8de8156ae9e34826376381bc0a66d4f221fbcc5a240ec03b868853d07f89adb.webp
  • C https://ik.imagekit.io/novatra/photos/0392ecd0c3e9348b7b6cc284e88e9e0a6ae837e6066510c724edc56788ce3519.webp
  • D https://ik.imagekit.io/novatra/photos/fcc1a3262d246eec1d72304e6b7d6008f4e802f6e24c510e4c9af7b7abbe67ce.webp

Step-by-Step Verified Solution

(a) (Acenaphthene)

JEE Main 2021 (Online) 1st September Evening Shift Chemistry - Basics of Organic Chemistry Question 131 English Explanation 1
→ 10 πe− in cyclic conjugation

⇒ Aromatic

"Note: For a compound with multiple cyclic rings to exhibit aromaticity, it must conform to Hückel's rule, which stipulates that the molecule should have (4n+2) π-electrons in the largest periphery of continuous conjugation. Rings with sp3 hybridized carbon atoms are not considered in this context. Despite their potential π-bonds, these rings cannot participate in resonance with π-bonds of the other rings due to the sp3 hybridization, and thus do not contribute to the overall aromaticity of the compound."

(b) JEE Main 2021 (Online) 1st September Evening Shift Chemistry - Basics of Organic Chemistry Question 131 English Explanation 2
→ 4 πe− in ring conjugation ⇒ Anti Aromatic

(c) JEE Main 2021 (Online) 1st September Evening Shift Chemistry - Basics of Organic Chemistry Question 131 English Explanation 3
⇒ 4 πe− in ring conjugation ⇒ Antiaromatic

(d) JEE Main 2021 (Online) 1st September Evening Shift Chemistry - Basics of Organic Chemistry Question 131 English Explanation 4
6πe− in ring conjugation ⇒ Aromatic

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