Dehydration means

Options

A. Removal of hydrogen molecule from adjacent carbons
B. Removal of hydrogen molecule from the same carbon
C. Removal of water moelcule from the same carbon as H and OH
D. Removal of H and OH from the adjacent carbons as water molecule

Answer

### Step-by-Step Solution:

1. **Understanding Dehydration**: Dehydration in chemistry refers to the process of removing water (H2O) from a substance. In the context of organic compounds, it often involves the removal of a hydroxyl group (-OH) and a hydrogen atom (H) from adjacent carbon atoms.

2. **Identifying the Correct Definition**: Among the given options, we need to identify which one correctly describes dehydration. The options are:
- Removal of hydrogen molecule from adjacent carbon.
- Removal of hydrogen molecule from the same carbon.
- Removal of another molecule from the same carbon as hydrogen and OH.
- Removal of hydrogen and OH from adjacent carbon as another molecule.

3. **Analyzing the Options**:
- **Option 1**: Removal of hydrogen molecule from adjacent carbon - This describes dehydrogenation, not dehydration.
- **Option 2**: Removal of hydrogen molecule from the same carbon - This is incorrect as it does not involve the removal of -OH.
- **Option 3**: Removal of another molecule from the same carbon as H and OH - This is also incorrect because it does not specify adjacent carbon atoms.
- **Option 4**: Removal of hydrogen and OH from adjacent carbon as another molecule - This is the correct definition of dehydration.

4. **Example of Dehydration**: Consider propanol (CH3-CH2-CH2-OH). When treated with sulfuric acid (H2SO4), the -OH group and a hydrogen atom from an adjacent carbon are removed, resulting in the formation of propene (CH3-CH=CH2). This illustrates the dehydration process.

5. **Conclusion**: Therefore, dehydration means the removal of hydrogen and hydroxyl (OH) groups from adjacent carbon atoms, leading to the formation of a double bond or an alkene.

### Final Answer:
Dehydration means the removal of hydrogen and hydroxyl (OH) from adjacent carbon atoms as water (H2O).

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