Why can breathing become difficult at altitude even when the percentage of O2 remains nearly similar?
Answer and explanation
Correct answer: Because air pressure and the partial pressure of O2 decrease
The governing concept is partial pressure. Although the fraction of oxygen in dry air remains close to 21%, total atmospheric pressure falls with altitude. By Dalton’s law, oxygen partial pressure equals its fraction multiplied by total pressure; therefore, its partial pressure also falls. Each breath then provides fewer oxygen molecules to the lungs, making respiration difficult. Option B is correct, while A, C and D describe processes that do not explain altitude-related breathing difficulty.
Frequently asked questions
What is the correct answer to this question?
Because air pressure and the partial pressure of O2 decrease
Why is this the correct answer?
The governing concept is partial pressure. Although the fraction of oxygen in dry air remains close to 21%, total atmospheric pressure falls with altitude. By Dalton’s law, oxygen partial pressure equals its fraction multiplied by total pressure; therefore, its partial pressure also falls. Each breath then provides fewer oxygen molecules to the lungs, making respiration difficult. Option B is correct, while A, C and D describe processes that do not explain altitude-related breathing difficulty.
Which subject and chapter does this question cover?
This is a Class 11 Accountancy question. Chapter: Theory Base of Accounting. Topic: accounting principles.
