Which of the following substances, when dissolved and oxidized in atmospheric…

Concept

Acid rain forms when certain atmospheric pollutants react with water and oxygen to produce acids that lower the pH of precipitation.

The acid formed depends on the elements present in the pollutant; a sulfur-containing oxide can produce sulfur-based acids.

Application

1. Sulphur dioxide dissolves in atmospheric water and first forms sulfurous acid: SO2 + H2O → H2SO3.

2. In the presence of oxygen, sulfur dioxide is further oxidized; the resulting sulfur oxides form sulfuric acid in water, increasing rainwater acidity.

3. Therefore, the substance among the given choices that forms sulfurous and sulfuric acids is sulphur dioxide.

Contrast

• Hydrogen peroxide is an oxidizing peroxide and does not contain sulfur, so it cannot form sulfurous or sulfuric acid.

• Nitrogen monoxide can participate in nitrogen-oxide chemistry, but it contains no sulfur and therefore cannot form the sulfur-based acids named in the question.

• Carbon dioxide forms weak carbonic acid in water, which explains the slight natural acidity of ordinary rain, not the sulfur-based acids specified here.

Cross-check

Both the reactant and the acids named in the stem must contain sulfur; sulphur dioxide satisfies this element-balance check.

Result

Hence, the answer is sulphur dioxide.