Which of the following is heterocyclic compound?

Options

A. Methane
B. Methyl alcohol
C. Cyclobutane
D. Pyridine

Explanation

To determine which of the given compounds is a heterocyclic compound, we need to understand the definitions and characteristics of homocyclic and heterocyclic compounds.

### Step-by-Step Solution:

1. **Understand the Definitions**:
- **Homocyclic Compounds**: These are cyclic compounds where all the atoms in the ring are of the same type (usually carbon). The term "homo" means "same."
- **Heterocyclic Compounds**: These are cyclic compounds that contain at least one atom in the ring that is different from carbon (such as nitrogen, oxygen, or sulfur). The term "hetero" means "different."

2. **Analyze Each Compound**:
- **Methane (CH₄)**: This is an open-chain alkane and not cyclic. Therefore, it cannot be a heterocyclic compound.
- **Methyl Alcohol (CH₃OH)**: This is also an open-chain compound (not cyclic) and thus is not a heterocyclic compound.
- **Cyclobutane (C₄H₈)**: This is a cyclic compound, but all the atoms in the ring are carbon atoms. Therefore, it is a homocyclic compound.
- **Pyridine (C₅H₅N)**: This compound has a ring structure that includes one nitrogen atom along with carbon atoms. Since it contains a different atom (nitrogen), it qualifies as a heterocyclic compound.

3. **Conclusion**:
- Among the given options, the only heterocyclic compound is **Pyridine**.

### Final Answer:
The heterocyclic compound from the options provided is **Pyridine**.

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