Question

Greenhouse effect is caused by

• A. \(NO_2\)
• B. CO
• C. NO
• D. \(CO_2\)

Hint:

While many gases are present in the atmosphere, the key greenhouse gases to remember are \(H_2O\), \(CO_2\), \(CH_4\), and \(N_2O\).
Symmetrical diatomic molecules like \(N_2\) and \(O_2\) are not greenhouse gases.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
We need to identify which of the given gases is a primary cause of the greenhouse effect.

Step 2: Key Formula or Approach:
The greenhouse effect is the process by which certain gases in the atmosphere trap heat by absorbing infrared radiation emitted from the Earth's surface.
These gases are known as greenhouse gases. To be a greenhouse gas, a molecule must have a changing dipole moment when it vibrates.

Step 3: Detailed Explanation:
Let's analyze the gases:
- The most important greenhouse gases are Water Vapor (\(H_2O\)), Carbon Dioxide (\(CO_2\)), Methane (\(CH_4\)), Nitrous Oxide (\(N_2O\)), and Ozone (\(O_3\)).
-

(D) \(CO_2\): Carbon dioxide is a major greenhouse gas. It is the most significant long-lived greenhouse gas contributing to modern climate change.
-

(A) \(NO_2\): Nitrogen dioxide is a greenhouse gas but its contribution is less significant than \(CO_2\).
-

(B) CO, (C) NO: Carbon monoxide and nitric oxide are not significant greenhouse gases themselves, although they can indirectly affect atmospheric chemistry.
Comparing the options, \(CO_2\) is the most prominent and direct cause of the enhanced greenhouse effect.

Step 4: Final Answer:
The greenhouse effect is caused by \(CO_2\).