Which of the following reagents is used in the reaction shown below?
Benzoyl chloride $\stackrel{?}{\longrightarrow}$ Benzaldehyde

Explain the method of preparation of aldehydes and ketones from nitrile compounds.

Write the structures of products of the following reactions:
$(i)$ Benzene + $C_{2}H_{5}COCl$ $\xrightarrow{\text{Anhyd. } AlCl_{3}, CS_{2}}$
$(ii)$ $(C_{6}H_{5}CH_{2})_{2}Cd + 2 CH_{3}COCl \rightarrow$
$(iii)$ $H_{3}C - C \equiv C - H$ $\xrightarrow{Hg^{2+}, H_{2}SO_{4}}$
$(iv)$ $p$-Nitrotoluene $\xrightarrow{1. CrO_{2}Cl_{2}, 2. H_{3}O^{+}}$

Conversion of benzene to acetophenone can be brought about by

Enumerate different methods to prepare aldehyde compounds.

What is the product formed by the reaction of chromyl chloride and toluene?