Step 1: Understanding the Question:
We need to identify the oxidation product of phenol when treated with chromium trioxide. Step 2: Detailed Explanation:
Phenol undergoes oxidation with strong oxidizing agents like chromic acid (formed by \( \text{Na}_2\text{Cr}_2\text{O}_7/\text{H}_2\text{SO}_4 \)) or chromium trioxide (\( \text{CrO}_3 \)).
The oxidation process results in a conjugated diketone structure known as p-benzoquinone.
\[ \text{C}_6\text{H}_5\text{OH} \xrightarrow{\text{CrO}_3} \text{O}=\text{C}_6\text{H}_4=\text{O (p-benzoquinone)} \] Step 3: Final Answer:
The product is p-benzoquinone.
