Question

Which of these statements is/are true about the given sample of air?
Nitrogen - 78%
Oxygen- 16.4%
Carbon dioxide - 4.4%
A. Dissolved air from pond water
B. Fresh air from a field
C. Exhaled air
D. Polluted air near a factory

Answer 1

Hint: The air which we inhale and exhale isn't pure oxygen or carbon dioxide respectively. As we all know that our body and the cells inside it requires more oxygen to breathe and to perform its regular functions and our surroundings don’t provide us with an exclusive supply of oxygen.

Complete answer: Inhaled air has the composition of approximately 79% nitrogen and 20.95% oxygen by volume and little amounts of other gases including argon, carbon dioxide, neon, helium, and hydrogen. The gas exhaled is around 4% to 5% to by volume of carbon dioxide, approximately counting to a 100-fold increase over the inhaled amount.
1. When we breathe out we release the same air that we inhaled in the first place.
2. Although, the composition of the air remains almost equivalent with respect to other gases, except for oxygen and carbon dioxide.
3. The quantity of inhaled air contains 21% oxygen and 0.04% carbon dioxide, while the air we exhale contains 16.4% of oxygen and 4.4% of carbon dioxide.
4. This is often because our cells use oxygen from the inhaled air to release energy and release carbon dioxide as a byproduct of the cellular respiration process.
5. During the respiration process, the entire composition of the air that we inhale also depends on our surrounding environment.
6. For example, the underwater divers would obviously inhale air containing more oxygen or helium. Similarly, the spacesuits worn by astronauts supplies pure oxygen for them to inhale in space.

So, the correct answer is option C. Exhaled air.

Note: It is important to know the composition of gases in our breath by breath analysis as it may lead to the diagnosis of underlying respiratory disorders and several other lung diseases, in case the values of the tests deviate from the normal recorded values.