# Why is oxygenated water not H2O2?

Oxygenated water has become popular for a variety of uses recently - for health purposes internally as well as enhanced wound healing.

Anyhow, my dad asked me recently if I knew how it is that oxygenated water does not become hydrogen peroxide. I don't know the answer to it; but it got me thinking... How does this work? Does the oxygen not bond to the water molecule? If so, how does the bottle of water not just out gas when ever it is opened until the amount of oxygen contained in the bottle is equal to that of the room air.

• Oh, if oxygenated water did change to hydrogen peroxide, I shouldn't have been alive now! Some reactions, just don't like to happen. – It's Over Feb 7 '15 at 15:55
• Sorry but anyone foolish enough to buy oxygenated water is an idiot wasting money. – MaxW Jan 7 '18 at 18:43
• @MaxW I would have to agree! I just was more curious about the chemistry of the whole thing :) – L.B. Feb 9 '18 at 18:43

## 3 Answers

The oxygen is dissolved in the water, just as salt can be dissolved. It does not (to any appreciable degree) combine with water molecules to form hydrogen peroxide.

The reason that oxygenated water is not fizzy like soda water (CO2) is the solubility of oxygen in water is about 2% that of CO2. So the amount of bubbles formed when the cap is removed is only about 1/50 as much as for soft drinks. Or champagne.

• When CO2 is dissolved in water, part of it reacts with H2O to produce H2CO3. Similarly part of the dissolved oxygen reacts with H2O to produce H2O2, doesn't it? If not why? If yes, what's the equilibrium? – Petr Pudlák Feb 7 '15 at 9:19
• @PetrPudlák Not similar at all. The formation of peroxide is very unfavourable and requires a lot of energy. So it doesn't happen easily or spontaneously, totally unlike carbonic acid. – matt_black Feb 7 '15 at 12:16

I think the problem is that the reaction:

$\ce{2H2O2-> 2H2O + O2}$

is spontaneous, meaning that it proceeds (slowly) in standard conditions with no other inputs required. So far from oxygen combining with water, you have hydrogen peroxide spontaneously decomposing into water and oxygen.

First you need to know what is oxygenated water. It's actually form by adding additional oxygen to the water under pressure. It means it's a mixture, not a compound.

We know that a mixture is two or more substances mix together physically. However, hydrogen peroxide bonds chemically which is a compound.

So, we can conclude that oxygenated cannot be classified as hydrogen peroxide.