Question

while exhaling we say it is rich in carbon dioxide but it has more percentage of oxygen . explain

Answer 1

Dear student,

The percentage of oxygen and carbon dioxide in inhaled and exhaled air is as follows -

Inhaled air	Exhaled air
21% oxygen	16.4% oxygen
0.04% carbon dioxide	4.4% carbon dioxide

Thus, inhaled air is rich in oxygen and has more % of oxygen than exhaled air.
Whereas exhaled air is rich in carbon dioxide and has less % of oxygen as compared to inhaled air.
But the percentage of oxygen is more(16.4%) than that of carbon dioxide(4.4%) even in the exhaled air due to the composition of atmosphere being such.
In the atmosphere, 21% of air is oxygen , the entire oxygen is not utilised during respiration in our cells, only a part is used and the rest gets exhaled (16.4%).
Regards