Question

sulfur dioxide and nitrogen dioxide are both primary pollutants. what do they react with to form an acid?
water
soil

Explanation:

Sulfur dioxide ($\text{SO}_2$) reacts with water to form sulfurous acid ($\text{H}_2\text{SO}_3$), and nitrogen dioxide ($\text{NO}_2$) reacts with water to form nitric acid ($\text{HNO}_3$) and nitric oxide ($\text{NO}$). These reactions are key to the formation of acid rain, while soil does not drive the direct acid-forming reaction with these pollutants.

Answer:

Water