Question

An organic compound X(molecular formula C6H7O2N) has six carbon atoms in a ring system, two double bonds and a nitro group as substituent, X is

• A. homocyclic but not aromatic
• B. aromatic but not homocydic
• C. homocyclic and aromatic
• D. heterocyclic and aromatic

Answer 1

The Correct Option is A

To determine the correct option corresponding to compound X with the molecular formula C_6H_7O_2N, let's follow a step-by-step reasoning process:

1. First, examine the molecular formula: C_6H_7O_2N. It implies the compound consists of carbon, hydrogen, oxygen, and nitrogen atoms.
2. Focus on the 'ring system' detail with 'six carbon atoms'. This indicates a six-membered ring, likely forming the backbone of the structure.
3. The presence of 'two double bonds' further implies that these are located within this ring structure or involve the substituents, affecting aromaticity.
4. The 'nitro group' implies an -NO₂ substituent. Nitro groups are strong electron-withdrawing groups, often participating in resonance and affecting aromaticity.
5. Determine aromaticity:
   • Aromatic compounds should follow Huckel's rule: contain 4n + 2 π-electrons (where n is a non-negative integer).
   • The ring system with 6 carbon and 2 double bonds would have 4 π-electrons (each bond contributing 2 electrons), which does not satisfy 4n + 2.
6. Evaluate the choices:
   • Homocyclic but not aromatic: Indeed, the compound contains a carbon ring (homocyclic) but does not meet the Huckel's criterion for aromaticity.
   • Aromatic but not homocyclic: Incorrect. Due to the carbon ring nature, it is homocyclic and the lack of aromatic criteria fulfillment.
   • Homocyclic and aromatic: Incorrect. As discussed, it is not aromatic.
   • Heterocyclic and aromatic: Incorrect. There are no heteroatoms in the ring structure to make it heterocyclic.

Thus, from the given options, the correct answer is homocyclic but not aromatic.