Step 1 : Understanding the Question:
The topic of this question is the Identification of Organic Compounds, specifically focusing on the chemical properties of Phenols versus Alcohols and Ethers. We are given a molecular formula and three specific observations: water insolubility, solubility in $\text{NaOH}$, and reaction with bromine water to form a white precipitate. These "chemical clues" allow us to narrow down the functional group and the specific isomer involved.
Step 2 : Key Formulas and approach:
The approach involves analyzing each experimental observation:
1. Formula $\text{C}_7\text{H}_8\text{O}$: Indicates a high degree of unsaturation, likely an aromatic ring.
2. Solubility in $\text{NaOH}$: This is a classic test for acidity. Carboxylic acids and phenols dissolve in $\text{NaOH}$ by forming salts, while alcohols and ethers do not.
3. Bromine Water Test: Formation of a white precipitate is characteristic of highly activated aromatic rings (like phenols or amines) undergoing electrophilic substitution.
Step 3 : Detailed Explanation:
The molecular formula $\text{C}_7\text{H}_8\text{O}$ can represent several isomers, including Benzyl Alcohol, Anisole (Methoxybenzene), and the three Cresols ($o, m, p$).
Observation 1: Solubility in aqueous $\text{NaOH}$. Benzyl Alcohol (Option A) is a neutral alcohol and does not react with $\text{NaOH}$. Anisole/Methoxybenzene (Options B and D) are ethers, which are also non-acidic and insoluble in $\text{NaOH}$.
Cresols are phenolic compounds. Phenols are acidic ($pKa \approx 10$) and react with $\text{NaOH}$ to form sodium phenoxides, which are ionic and soluble in water. This identifies the compound as a Cresol.
Observation 2: Bromine water reaction. Phenols have a strongly activating $-OH$ group that makes the benzene ring highly reactive toward electrophiles like Bromine.
When a phenol (like $o$-Cresol) is treated with bromine water, it undergoes polybromination at the available ortho and para positions, resulting in the formation of a brominated derivative that appears as a white precipitate.
Since $o$-Cresol ($C_7H_8O$) is a phenol and exhibits all these properties, it fits the description perfectly.
Step 4 : Final Answer:
The acidic nature and reaction with bromine water identify the compound as a phenolic derivative, specifically $o$-Cresol. The correct option is (C).