OR, MORE COMMONLY..........
2H2O⇌H3O++HO−
This is the so-called autoprotolysis reaction of water, which has been meticulously studied, and underlies our conception of acid/base chemistry.
The hydronium ion, H3O+, and hydroxide ion, HO−, are conceived to be the characteristic cation and characteristic anion of the WATER SOLVENT, i.e. the acidium ion, and the hydroxide ion. I write conceived because the acidium ion in water solution is probably H5O+2 or H7O+3, a cluster of several water molecules WITH AN EXTRA H+ associated with the cluster. We write H+, or H3O+ to represent this species, i.e. as a shorthand.
In water at 298⋅K,
2H2O⇌H3O++HO− Kw=[H3O+][HO−]=10−14.
Given that this is a bond-breaking reaction, how do you think this equilibrium would evolve AT HIGHER TEMPERATURES? (If you are not an undergrad, don't bother with this question).
