Nitrogen Oxide is:

Nitrogen Oxide is:

• A. A combination of nitrogen and oxygen; used for the combustion of fossil fuels in vehicles and power plants
• B. A dense black smoke
• C. A colorless gas that neutralizes acidity
• D. A liquid oxide used in water treatment

Answer: (A)

Nitrogen oxide is formed when fossil fuels burn at high temperatures, creating nitrogen-oxygen compounds (such as NO and NO2) that are emitted in vehicle and power-plant exhaust. These are gases produced by the combustion process, not a dense black smoke, not a liquid used in water treatment, and not a substance that neutralizes acidity. Describing nitrogen oxide as a combination of nitrogen and oxygen that forms during high-temperature combustion best captures what it is and where it comes from.

Nitrogen oxide is formed when fossil fuels burn at high temperatures, creating nitrogen-oxygen compounds (such as NO and NO2) that are emitted in vehicle and power-plant exhaust. These are gases produced by the combustion process, not a dense black smoke, not a liquid used in water treatment, and not a substance that neutralizes acidity. Describing nitrogen oxide as a combination of nitrogen and oxygen that forms during high-temperature combustion best captures what it is and where it comes from.