Discuss the role of Lewis acids in the preparation of aryl bromides and chlorides in the dark.

Explanation

The role of Lewis acid catalyst `(FeCl_(3),FeBr_(3)`, etc.) in the preparation of aryl chlorides or bromides from arenes is to generate the electrophiles `Cl^(+)` or `Br^(+)` from the corresponding halogens. These electrophiles then react with arenes.