Problem 20 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

Which of the following is a set of green house gases? (a) \(\mathrm{CH}_{4}, \mathrm{O}_{3}, \mathrm{~N}_{2}, \mathrm{SO}_{2}\) (b) \(\mathrm{O}_{3}, \mathrm{~N}_{2}, \mathrm{CO}_{2}, \mathrm{NO}_{2}\) (c) \(\mathrm{O}_{3}, \mathrm{NO}_{2}, \mathrm{SO}_{2}, \mathrm{Cl}_{2}\) (d) \(\mathrm{CO}_{2}, \mathrm{CH}_{4}, \mathrm{~N}_{2} \mathrm{O}, \mathrm{O}_{3}\)

Step-by-Step Solution

Answer

The correct set of greenhouse gases is (d): \(\mathrm{CO}_{2}, \mathrm{CH}_{4}, \mathrm{N}_{2}\mathrm{O}, \mathrm{O}_{3}\).

Step 1: Understanding Greenhouse Gases

Greenhouse gases are those that can trap heat in the Earth's atmosphere, contributing to the greenhouse effect. Common greenhouse gases include carbon dioxide (\(\mathrm{CO}_{2}\)), methane (\(\mathrm{CH}_{4}\)), nitrous oxide (\(\mathrm{N}_{2}\mathrm{O}\)), and ozone (\(\mathrm{O}_{3}\)). Other gases that are commonly mistaken as greenhouse gases, like nitrogen (\(\mathrm{N}_{2}\)), are not included because they don't significantly absorb infrared radiation.

Step 2: Analyzing Option (a)

Option (a) includes \(\mathrm{CH}_{4}\), which is a greenhouse gas, and \(\mathrm{O}_{3}\), also a greenhouse gas. However, \(\mathrm{N}_{2}\) and \(\mathrm{SO}_{2}\) are not considered greenhouse gases as they do not trap infrared radiation effectively. Therefore, this option does not contain a complete set of greenhouse gases.

Step 3: Analyzing Option (b)

Option (b) includes \(\mathrm{O}_{3}\) and \(\mathrm{CO}_{2}\), both of which are greenhouse gases. However, \(\mathrm{N}_{2}\) and \(\mathrm{NO}_{2}\) are not significant greenhouse gases. Hence, this option is not correct as it does not fully consist of greenhouse gases.

Step 4: Analyzing Option (c)

In option (c), \(\mathrm{O}_{3}\) is a greenhouse gas, but \(\mathrm{NO}_{2}\), \(\mathrm{SO}_{2}\), and \(\mathrm{Cl}_{2}\) are not considered greenhouse gases since they do not contribute significantly to the greenhouse effect. So, this option is incorrect as a set of greenhouse gases.

Step 5: Analyzing Option (d)

Option (d) contains \(\mathrm{CO}_{2}\), \(\mathrm{CH}_{4}\), \(\mathrm{N}_{2}\mathrm{O}\), and \(\mathrm{O}_{3}\), all of which are recognized as greenhouse gases. This set effectively traps heat and contributes to the greenhouse effect, making it the correct option.

Key Concepts

Carbon dioxide

Carbon dioxide (\(\mathrm{CO}_{2}\)) is a vital component of the Earth's atmosphere and plays a crucial role as a greenhouse gas. It is produced through natural processes such as respiration and volcanic eruptions, as well as human activities like burning fossil fuels and deforestation. Carbon dioxide effectively absorbs infrared radiation, which contributes to the warming of the earth's surface by trapping heat.

• Sources include combustion of coal, oil, and natural gas.
• A key contributor to climate change due to its abundance and longevity in the atmosphere.
• Human influence has significantly increased its concentration by over 40% since the industrial revolution.

Methane

Methane (\(\mathrm{CH}_{4}\)) is another powerful greenhouse gas common in the Earth's atmosphere. Though less abundant than carbon dioxide, it is much more effective at trapping heat on a per-molecule basis, making it a critical component in discussions of global warming.

• Produced naturally through processes like the decomposition of organic matter in wetlands and digestion in animals.
• Human activities such as agriculture (particularly livestock) and natural gas extraction also contribute to methane emissions.
• Methane has a relatively short atmospheric lifetime of around 12 years but has a significant immediate impact on atmospheric warming.

Nitrous oxide

Nitrous oxide (\(\mathrm{N}_{2}\mathrm{O}\)) is a potent greenhouse gas with both natural and anthropogenic sources. It is part of the nitrogen cycle and occurs naturally through processes in soils and oceans. However, human activities like industrial agriculture have greatly increased its levels.

• Major sources include agricultural practices that utilize nitrogen-based fertilizers.
• Acts as a powerful greenhouse gas with a global warming potential 298 times that of carbon dioxide over a 100-year period.
• Also plays a role in depleting the ozone layer, which protects Earth from harmful ultraviolet rays.

Ozone

Ozone (\(\mathrm{O}_{3}\)) plays a dual role in the Earth's atmosphere. While high-altitude ozone forms the ozone layer that shields the Earth from ultraviolet radiation, ground-level ozone acts as a greenhouse gas. It is different from other greenhouse gases because it forms through photochemical reactions.

• Formed by the reaction of sunlight with pollutants like nitrogen oxides and volatile organic compounds.
• While it has a short atmospheric lifetime, it is a strong greenhouse gas and contributes to smog pollution.
• Ozone pollution is associated with human health problems such as respiratory issues.