NCERT Solutions Curiosity Chapter 11 .1 Air — In-text Questions
Book page 20911 Updated on2026-09-05
Q1.
The air which surrounds the Earth is a mixture of gases. Can you name some gases which are present in the air?
Answer
Air is not one single gas — it is a mixture. Fig. 11.1 shows this as 100 squares, and each square stands for 1 per cent.
Out of 100 squares — 78 nitrogen + 21 oxygen + 1 argon, carbon dioxide and other gases = 100
Fig. 11.1 drawn as 100 squares — 78 squares of nitrogen, 21 of oxygen and 1 of argon, carbon dioxide and other gases.
Nitrogen — the largest part of air, about 78%.
Oxygen — about 21%; this is the gas we need to stay alive.
Argon, carbon dioxide and other gases — together only about 1%.
Air also carries water vapour and fine dust, whose amount keeps changing.
Why the tiny 1% matters: carbon dioxide is only a small part of air, yet plants use it to make food, and it is the gas released when fossil fuels burn. A small share does not mean a small role.
Did you know?Percentage means “the number of parts in 100”, written with the symbol %. So 21% oxygen means 21 parts of every 100 parts of air are oxygen.