Chapter-11 Air — Online MCQ Test
SCIENCE · Samacheer Kalvi 8th · Tamil Nadu State Board
Practice Chapter-11 Air with a free chapter-wise online MCQ test.
This chapter covers: oxygen nitrogen atmosphere Explains the composition properties and importance of air.
AI-generated questions from basic to board-exam level, with instant results and explanations.
Chapter-11 Air — Important Questions & Answers
What is the major component of air by volume?
- A. Oxygen
- B. Nitrogen
- C. Carbon dioxide
- D. Water vapour
Answer: B. Nitrogen
Nitrogen makes up the largest part of air, about 78%. It is the main component of the atmosphere.
Nitrogen makes up the largest part of air, about 78%. It is the main component of the atmosphere.
Which gas in air is essential for burning and respiration?
- A. Oxygen
- B. Nitrogen
- C. Argon
- D. Helium
Answer: A. Oxygen
Oxygen supports combustion and is needed for breathing in living organisms.
Oxygen supports combustion and is needed for breathing in living organisms.
Why do higher mountain regions feel colder and have less breathable air than plains?
- A. Air pressure and oxygen availability are lower at high altitudes
- B. Nitrogen disappears at high altitudes
- C. Oxygen changes into carbon dioxide
- D. Air becomes heavier at high altitudes
Answer: A. Air pressure and oxygen availability are lower at high altitudes
As altitude increases, air pressure decreases, so the amount of oxygen available per breath is lower.
As altitude increases, air pressure decreases, so the amount of oxygen available per breath is lower.
Which statement is correct about air?
- A. Air is a single gas
- B. Air is a mixture of gases
- C. Air contains only oxygen and nitrogen
- D. Air has no water vapour or dust
Answer: B. Air is a mixture of gases
Air is a mixture of several gases such as nitrogen, oxygen, carbon dioxide, water vapour, and noble gases.
Air is a mixture of several gases such as nitrogen, oxygen, carbon dioxide, water vapour, and noble gases.
Which pair is correctly matched?
- A. Nitrogen – supports combustion
- B. Oxygen – helps in respiration
- C. Carbon dioxide – major component of air
- D. Water vapour – main gas in air
Answer: B. Oxygen – helps in respiration
Oxygen is required for respiration in living organisms. The other options are incorrect because nitrogen does not support burning and carbon dioxide is not the major gas in air.
Oxygen is required for respiration in living organisms. The other options are incorrect because nitrogen does not support burning and carbon dioxide is not the major gas in air.