Question

3. Two non-metallic oxides A and B are produced by the burning of fossil fuels. A pollutes both air and water. B does not cause water pollution and its presence in water is essential. It causes air pollution. Identify A and B.

• A. ${\mathrm{NO}}_2$, ${\mathrm{SO}}_2$
• B. ${\mathrm{SO}}_2,\mathrm{CO}$
• C. ${\mathrm{SO}}_2,{\mathrm{CO}}_2$
• D. ${\mathrm{CO}}_2,{\mathrm{NO}}_2$

Answer 1

The correct option is C

${\mathrm{SO}}_2,{\mathrm{CO}}_2$

Explanation:

• It is given that A as well as B are non-metallic oxides and produces by the burning of fossil fuels.
• A pollutes both air and water. So, A must be an oxide of Nitrogen or Sulphur i.e. Nitrogen dioxide $\left({\mathrm{NO}}_2\right)$ or Sulphur dioxide $\left({\mathrm{SO}}_2\right)$ respectively.
• B does not cause water pollution and its presence in water is essential. It means B should be Carbon dioxide $\left({\mathrm{CO}}_2\right)$ because it is present in water which is essential for aquatic plants. But it causes air pollution and is a major contributor to global warming.
• Hence, A is ${\mathrm{SO}}_2$ and B is${\mathrm{CO}}_2$.

Thus, option (C) is the correct answer.