Problem 12 - A Complete Resource Book in Chemistry for JEE Main

Question

The major components of the atmosphere are (a) \(\mathrm{CO}_{2}\) and \(\mathrm{N}_{2}\) (b) \(\mathrm{O}_{3}\) and \(\mathrm{SO}_{2}\) (c) \(\mathrm{CO}\) and \(\mathrm{CO}_{2}\) (d) \(\mathrm{N}_{2}\) and \(\mathrm{O}_{2}\)

Step-by-Step Solution

Answer

The major components of the atmosphere are (d) N_2 and O_2.

Step 1: Understand the Question

The problem asks us to identify the major components of the Earth's atmosphere from a list of options. Earth's atmosphere is a mixture of gases, and we need to understand which of these gases are present in the highest concentration.

Step 2: Recall Composition of Atmosphere

Earth's atmosphere is primarily composed of nitrogen (N_2) and oxygen (O_2), with nitrogen making up approximately 78% and oxygen about 21% of the atmosphere. There are other gases present in smaller quantities, but they are not the major components.

Step 3: Evaluate Options

Examine each option: - (a) CO_2 and N_2: N_2 is major, but CO_2 is not. - (b) O_3 and SO_2: Neither O_3 nor SO_2 are major components. - (c) CO and CO_2: Neither are major components. - (d) N_2 and O_2: Both are major components.

Step 4: Choose the Correct Option

Based on the evaluation, the correct answer is (d) N_2 and O_2, as they are the gases that make up the majority of Earth's atmosphere.

Key Concepts

Earth's Atmosphere

The Earth's atmosphere is a fascinating layer of gases surrounding our planet, held in place by Earth's gravity. This atmosphere is essential for many processes that support life. It acts like a protective shield that keeps living organisms safe from harmful ultraviolet rays, helps regulate temperature, and enables the breathing processes for most life forms.

Comprising multiple layers such as the troposphere, which is closest to the Earth, and the stratosphere above it, the atmosphere has a complex structure that allows for weather patterns and climate to occur. Because of this, the atmosphere not only provides life-sustaining oxygen but also plays a crucial role in various natural phenomena.

• Troposphere: the layer closest to Earth where weather occurs.
• Stratosphere: contains the ozone layer and absorbs UV radiation.
• Mesosphere, Thermosphere, and Exosphere: Outer layers with different characteristics and functions.

By studying the atmosphere, scientists can better predict weather changes and understand the planet’s climate systems.

Major Gases in Atmosphere

Earth's atmosphere is mainly composed of a mixture of different gases. Although the air may seem uniform, it contains diverse gases each with unique properties and roles. The major gases are nitrogen and oxygen, which dominate the composition.

Other gases like argon, carbon dioxide, neon, helium, methane, and others are present in much smaller amounts. Despite their minimal presence, these trace gases can significantly influence the environment and climate.

• Nitrogen ( N_2 ): Approximately 78% of the atmosphere.
• Oxygen ( O_2 ): Roughly 21% of the atmosphere.
• Argon ( Ar ): A noble gas making up about 0.93% of the atmosphere.
• Carbon Dioxide ( CO_2 ): Though only about 0.04% of the atmosphere, it plays a key role in the greenhouse effect.

These gases are continuously cycled through the environment by natural processes such as photosynthesis, respiration, and nitrogen fixation. Understanding their distribution and roles aids scientists in addressing environmental challenges.

Nitrogen and Oxygen in Atmosphere

Nitrogen and oxygen are the twin giants of Earth's atmosphere, responsible for forming the bulk of the air we breathe. Nitrogen is the most abundant, making up about 78%, but on its own, it is relatively inert. However, it is vital for life since it is a crucial component of amino acids and nucleic acids in living organisms.

Oxygen, while slightly less abundant at around 21%, is highly reactive. It is essential for cellular respiration, a process by which organisms generate energy by consuming oxygen and releasing carbon dioxide. This process is critical for the survival of many plants and animals.

• Nitrogen: Mainly inactive but vital for growth and reproduction in form of compounds.
• Oxygen: Supports burning (combustion) and is crucial for aerobic life forms.

These two gases not only form the foundation of life on Earth but also contribute to the stable climate. Balancing their levels in the atmosphere is crucial for maintaining ecological harmony.