Question

One of the following acts as a secondary pollutant.

• A. Br${}_2$
• B. Cl${}_2$
• C. CO
• D. HNO${}_3$

Answer 1

The correct option is D HNO${}_3$

Secondary pollutants are the pollutants formed by the chemical reaction between primary pollutants in the presence of sunlight e.g., sulphuric acid, nitrogen dioxide and ozone. Nitric oxides, when dissolved in water, produces nitric acid. Hence, nitric acid (HNO${}_3$) is a secondary air pollutant. It is responsible for acid rains.

Thus, the correct answer is option D.