Hello!

Sure let's talk about that.

The equation I'm assuming you're asking about is the breakdown of water molecules

H2O --> H+ + OH-

2H2O --> H3O+ + OH-

in the real world, there will (almost) never be a scenario where you are dealing with one single water molecule.

It'll be billions and billions of water molecules all at the same time.

so it's kinda meaningless to just use this theoretical equation (H2O --> H+ + OH-)

when it doesn't reflect what's happening in the real world.

It turns out, in real life, the H+ that is formed, it doesn't just exist by itself,

it immediately attaches to a nearby water molecule, resulting in

H+ + H2O --> H3O+

So we try to write an equation that reflects this reality, with 2 water molecules involved :

2 H2O --> H3O+ + OH-