Question

Which from following compounds does NOT contain nitrogen in it?

• A. Thiophene
• B. Pyridine
• C. Pyrrole
• D. Piperidine

Hint:

Memorize the "Big Three" 5-membered aromatic heterocycles:
- Pyrrole contains Nitrogen (N).
- Furan contains Oxygen (O).
- Thiophene contains Sulphur (S).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Heterocyclic compounds are cyclic compounds that contain at least one atom other than carbon (heteroatom) in the ring. Common heteroatoms include Nitrogen, Oxygen, and Sulphur.

Step 2: Formula Application:
Analyze the heteroatom in each structure: - Pyridine ($C_5H_5N$): Nitrogen. - Pyrrole ($C_4H_5N$): Nitrogen. - Piperidine ($C_5H_{11}N$): Nitrogen. - Thiophene ($C_4H_4S$): Sulphur.

Step 3: Explanation:
Thiophene is a five-membered heterocyclic ring where the heteroatom is Sulphur. The other three options are all nitrogen-containing heterocycles.

Step 4: Final Answer:
The compound that does not contain nitrogen is Thiophene.