Answer:
To prevent formation of side products.
Explanation:
The nitric acid is inorganic acid and a strong oxidizing agent. It has no color in its pure form but it turns yellow overtime due to presence of nitrogen oxides. The nitric acid is always added dropwise because continuos addition of nitric acid causes the formation of side products in the reaction. The drop wise method is performed for usually 15 minutes. This process allows the formation of only mononitrated product.
