If you breathe pure co2 what will happen?

Answer 1

As long as you immediately breath out again and then inhale regular air, nothing. Prolonged exposure leads to rapid breathing, acidosis (increase in blood acidity), unconciousness, and finally death.

Answer 2

Within seconds of inhaling pure carbon dioxide, you will feel an uncontrollable urge to gasp for fresh air. If you are in control of the situation, you will not be able to "breath" CO2 for more than one or two breaths, due to this uncontrollable urge.

For the next minute or so of breathing normal air, you will continue to feel the strong (but controllable) need to breath rapidly, as though during intense exercise. This will be accompanied by an elevation in blood pressure and heart rate, and may be accompanied by near-blackout sensations, such strange effects on your vision, hearing, and balance.

Source: I've done it many times.

Answer 3

Carbon Monoxide is a gas, so you don't "eat it", per se; you breathe it. Unfortunately, if you do that, you will die, because the Carbon Monoxide binds to the hemoglobin in your blood more tightly than Oxygen, with the result that your body dies from Oxygen deprivation.

Answer 4

Nothing. you can get poisoning from too much of it though. Carbon monoxide is the dangerous one.