This reaction involves the oxidation of methylbenzene (toluene) using chromium trioxide chloride (\(\text{CrO}_2\text{Cl}_2\)). The result is the formation of benzaldehyde.
\[
\text{C}_6\text{H}_5\text{CH}_3 \xrightarrow{\text{CrO}_2\text{Cl}_2} \text{C}_6\text{H}_5\text{CHO}
\]