Animated Solution for Chemistry - Environmental Chemistry: Identify the wrong statements in the following

When tackling questions on environmental chemistry, it is crucial to have a crystal-clear understanding of the various phenomena that affect our atmosphere. This question is a classic test of your foundational knowledge regarding atmospheric pollution. Let's break down each statement like a detective to find the imposter.

Statement (a): Chlorofluorocarbons are responsible for ozone layer depletion. We know that Chlorofluorocarbons (CFCs) are notorious for their destructive behavior in the stratosphere. When UV radiation hits CFC molecules, they break apart and release highly reactive chlorine free radicals ($C{l}^{\bullet }$). A single chlorine radical can destroy thousands of ozone ($O_3$) molecules by converting them into ordinary oxygen ($O_2$). So, this statement is a solid, undeniable fact.

Statement (b): Green house effect is responsible for global warming. Imagine a car parked in the sun with its windows rolled up. The inside gets incredibly hot because the glass lets sunlight in but prevents the heat from escaping. The Earth's atmosphere does something similar. Greenhouse gases like $C{O}_2$, $C{H}_4$, and water vapor trap the infrared heat radiating from the Earth's surface. While a natural greenhouse effect is essential for life, the enhanced greenhouse effect caused by human activities leads to a dangerous rise in average global temperatures, known as global warming. This statement is also perfectly correct.

Statement (c): Ozone layer does not permit infrared radiation from the sun to reach the earth. Here is where we catch the lie! The ozone layer is our planet's sunscreen. Its primary job is to absorb high-energy, harmful Ultraviolet (UV) radiation from the sun, protecting living organisms from skin cancer and genetic damage. However, it is practically transparent to infrared radiation. Infrared rays, which we feel as heat, pass right through the ozone layer without any trouble. Therefore, claiming that the ozone layer blocks infrared radiation is factually incorrect.

Statement (d): Acid rain is mostly because of oxides of nitrogen and sulphur. When fossil fuels are burned, they release sulfur dioxide ($S{O}_2$) and nitrogen oxides ($N{O}_x$) into the air. These gases rise into the atmosphere and react with water vapor and oxygen to form sulfuric acid ($H_{2}S{O}_4$) and nitric acid ($HN{O}_3$). These acids then mix with rain, snow, or fog, falling to the ground as acid rain. This statement is absolutely true.

Since the question asks us to identify the wrong statement, the culprit is clearly statement (c). The ozone layer is a shield against UV rays, not infrared rays!