The preparation of phenol can be done via several methods. One common method is the **Caustic soda method**, where chlorobenzene reacts with sodium hydroxide.
\[
\text{C}_6\text{H}_5\text{Cl} + \text{NaOH} \xrightarrow{\Delta} \text{C}_6\text{H}_5\text{OH} + \text{NaCl}
\]
Here, chlorobenzene (C\(_6\)H\(_5\)Cl) reacts with sodium hydroxide (NaOH) in the presence of heat (Δ) to form phenol (C\(_6\)H\(_5\)OH) and sodium chloride (NaCl).
Final Answer:
\[
\boxed{\text{C}_6\text{H}_5\text{Cl} + \text{NaOH} \xrightarrow{\Delta} \text{C}_6\text{H}_5\text{OH} + \text{NaCl}}
\]