Question

Which one of the following is NOT a greenhouse gas?

• A. $CO_2$
• B. $CH_4$
• C. $H_2S$
• D. $H_2O$

Answer 1

The Correct Option is C

Step 1: Define greenhouse gases. Greenhouse gases trap heat in the Earth's atmosphere and contribute to the greenhouse effect. The major greenhouse gases include: \( \text{CO}_2 \) (Carbon dioxide) \( \text{CH}_4 \) (Methane) \( \text{H}_2\text{O} \) (Water vapor) \( \text{N}_2\text{O} \) (Nitrous oxide) Fluorinated gases (e.g., CFCs, HFCs) 

Step 2: Analyze the given options. \( \text{CO}_2 \): A well-known greenhouse gas. \( \text{CH}_4 \): Another potent greenhouse gas. \( \text{H}_2\text{S} \): Hydrogen sulfide is not a significant greenhouse gas; it is primarily associated with odor and toxicity. \( \text{H}_2\text{O} \): Water vapor is a natural greenhouse gas that plays a significant role in the greenhouse effect. 

Step 3: Identify the non-greenhouse gas. Among the options, \( \text{H}_2\text{S} \) is not classified as a greenhouse gas.