Which of these is the correct equation for the dissociation of water?

h2o + h2o+< ==> h2o + oh–
h2o + h2o < ==> h3o+ + oh–
h2o < ==> h+ + oh–
h+< ==> h2o + h2o+
h2o + oh–< ==> h2o+

H₂O + H₂O <==> H₃O⁺ + OH⁻   (option 2)

Explanation:

The equation can be resumed as this:

2H₂O ⇄  H₃O⁺ + OH⁻      Kw

Water can be an acid and a base because it is able to lose or win protons, and because it has also the ability to catch hydroxides or lose them. This compound are called amphoteric.

As it is an equilibrium, we talk about Kw, constant for water equilibrium, which values  1×10⁻14, where ¨[H₃O⁺] = [OH⁻]

the cold front replaces the warmer air at the ground level changing the wind to be breezy and denser.there is also an immediate drop in the temperature.