Oxygen reacts with virtually everything. Oxidizers, are what promotes the violent reaction in rocket fuel which propels the rocket. Anything that burns, burns because of the presence of oxygen. The more O2 the greater the rate of burning.

When I was in the USAF, I would service the F-4s with LOX (Liquid oxygen. This is what the pilots would breathe. I also served some other purposes but that was the main purpose. No, No, No! It was converted into its gaseous form first! Then the pilot would breathe it. We had to be careful handling it because of the low, cryogenic temperatures involved. Inevitably big drops would spill onto the flightline and our entertainment was to stomp on it with our boot heels. You had to have oily boot heels to do this. The pure O2 in great quantity would cause the oil to explode and it was like a firecracker going off under your heel! Cheap thrills! Somehow we kept them flying!

Water is known as the Universal Solvent. Anything, ANYTHING will dissolve in water, given a sufficient length of time and this is because of the oxygen component in H2O. Interesting stuff, this Oxygen.