What is dissociation of Water
The word dissociates mean break apart the bond.
When water dissociates, one of the hydrogen atoms leaves the water molecule. While doing so, it also leaves behind an electron but takes the proton with it.
So now, water H2O becomes a hydroxide OH(-) and it's negative because
- minus (-) 1 proton
- plus (+) 1 electron
Meantime, the hydrogen ion that has wandered off has no electron. It's unable to neutralize the positive charge on its proton so it ends up being a hydrogen ion with a positive charge H(+).
The hydrogen ion (which is just a proton) does not wander long by itself before it attaches to the oxygen atom of a second un-ionized water molecule. Together they form a hydronium ion H3O(+).