Question

why pure oxygen is not given to to a patient for inhaling, it is always mixed with a little amount of carbon dioxide ​

Answer 1

$\huge\textbf{Answer}$

We breathe air that is 21 percent oxygen.pure oxygen is generally bad, and sometimes toxic.

If you breathe air with a much higher than normal O2 concentration, the oxygen in the lungs overwhelms the blood’s ability to carry it away.

The result is that free oxygen binds to the surface proteins of the lungs, interferes with the operation of the central nervous system and also attacks the retina.

Contrary to popular myth, hyperventilating air at ordinary pressures never causes oxygen toxicity (the dizziness is due to CO2 levels dropping too low), but breathing oxygen at pressures of 0.5 bar or more (roughly two and a half times normal) for more than 16 hours can lead to irreversible lung damage and, eventually, death.

Answer 2

because when pure oxygen enter our body it mix with blood and can burn our body that's why a little amount of carbon dioxide oxide is gives with oxygen