Which of the following pairs of compounds may be regarded both as position isomers and functional isomers?

Options

A. o-crestol and p-crestol
B. Benzyl alcohol and methoxybenzene
C. benzyl alcohol and o-cresol
D. benzyl alcohol and benzyl methyl ether

Explanation

To determine which pair of compounds can be regarded both as position isomers and functional isomers, we will analyze each option step by step.

### Step 1: Analyze Option A - O-Cresol and Para-Cresol
- **Structures**:
- O-Cresol (ortho-cresol) has the hydroxyl (OH) group and a methyl (CH3) group on adjacent carbon atoms.
- Para-Cresol has the OH group and the CH3 group on opposite sides of the benzene ring.
- **Position Isomerism**: Yes, these are position isomers because the position of the OH group changes relative to the CH3 group.
- **Functional Isomerism**: No, both compounds are phenols and do not change their functional group.
- **Conclusion**: This option does not satisfy both criteria.

### Step 2: Analyze Option B - Benzyl Alcohol and Methoxybenzene
- **Structures**:
- Benzyl alcohol has the structure C6H5CH2OH.
- Methoxybenzene (anisole) has the structure C6H5OCH3.
- **Position Isomerism**: No, these compounds do not differ in the position of the same functional group.
- **Functional Isomerism**: Yes, they differ in functional groups (alcohol vs. ether).
- **Conclusion**: This option does not satisfy both criteria.

### Step 3: Analyze Option C - Benzyl Alcohol and Ortho-Cresol
- **Structures**:
- Benzyl alcohol: C6H5CH2OH.
- Ortho-Cresol: C6H4(OH)(CH3) with the OH and CH3 groups on adjacent carbons.
- **Position Isomerism**: Yes, the position of the OH group is different in these two compounds.
- **Functional Isomerism**: Yes, one is an alcohol and the other is a phenol.
- **Conclusion**: This option satisfies both criteria.

### Step 4: Analyze Option D - Benzyl Alcohol and Benzyl Methyl Ether
- **Structures**:
- Benzyl alcohol: C6H5CH2OH.
- Benzyl methyl ether: C6H5OCH3.
- **Position Isomerism**: No, these compounds do not differ in the position of the same functional group.
- **Functional Isomerism**: Yes, they differ in functional groups (alcohol vs. ether).
- **Conclusion**: This option does not satisfy both criteria.

### Final Answer
The correct answer is **Option C**: Benzyl Alcohol and Ortho-Cresol, as they exhibit both position isomerism and functional isomerism.

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