Question

41. Which of the following statements is incorrect?

• A. Burning of dry leaves causes air pollution
• B. Oxygen helps in burning
• C. We breathe in carbon dioxide
• D. Noble gases are present in the air

Answer 1

The correct option is C

We breathe in carbon dioxide

Explanation of correct option:

(C) We breathe in carbon dioxide:

• During the process of respiration, we breathe in oxygen and breathe out carbon dioxide.

Explanation of incorrect option:

(A) Burning of dry leaves causes air pollution:

• It contains harmful chemicals like carbon monoxide which can mix with blood and reduce the amount of oxygen in the blood.

(B) Oxygen helps in burning:

• The burning of substances in the presence of oxygen is known as combustion.
• Therefore, oxygen helps the chemical process combustion.

(D) Noble gases are present in the air:

• Air contains 78% nitrogen, 21% oxygen, 0.9% argon, and the rest of all other gases like carbon dioxide, water vapor, neon, etc.
• All noble gases are present in the air. Such as argon, neon, krypton, and xenon except for helium and radon.
• All noble gases are present in about 1% of the air.

Conclusion: Hence, option (C) is correct.