Ortho-dihydroxy benzene is :

Options

A. Carvacrol
B. Resorcinol
C. Catechol
D. Orcinol

Answer

To determine what ortho-dihydroxybenzene is, we need to analyze the options provided and identify the structure that corresponds to this name.

### Step 1: Understand the term "ortho-dihydroxybenzene"
Ortho-dihydroxybenzene refers to a benzene ring that has two hydroxyl (–OH) groups attached to it at the ortho positions. The ortho position means that the two –OH groups are adjacent to each other on the benzene ring.

### Step 2: Analyze the options
1. **Carvacrol**: This compound has a benzene ring with a methyl group and an isopropyl group along with one –OH group. It does not have two –OH groups at the ortho position, so it cannot be ortho-dihydroxybenzene.

2. **Resorcinol**: This compound has two –OH groups, but they are located at the first and third positions on the benzene ring, making it a meta-dihydroxybenzene. Therefore, it does not fit the definition of ortho-dihydroxybenzene.

3. **Catechol**: This compound has two –OH groups located at the first and second positions on the benzene ring, which are indeed ortho to each other. Thus, catechol is the correct structure for ortho-dihydroxybenzene.

4. **Orzinole**: This compound has two –OH groups at the first and third positions, similar to resorcinol, and also includes a methyl group. Hence, it does not qualify as ortho-dihydroxybenzene.

### Step 3: Conclusion
Based on the analysis, the only compound that corresponds to ortho-dihydroxybenzene is **catechol**.

### Final Answer:
**Ortho-dihydroxybenzene is catechol.**

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