Dissociation of water molecules leads to acidic and basic conditions that affect living organisms.
Dissociation of water molecules leads to acidic and basic conditions that affect living organisms.
Occasionally, a hydrogen atom participating in a hydrogen bond between two water molecules shifts from one
molecule to the other. When this happens, the hydrogen atom leaves its electron behind,
and what is actually transferred is a hydrogen ion, a single proton with a charge of 1 +.
The water molecule that lost a proton is now a hydroxide ion (OH − ),
which has a charge of 1−.
The proton binds to the other water molecule, making that molecule a hydronium ion (H3O+).
We can picture the chemical reaction this way: Although this is what actually happens, we can think of the process in a
simplified way, as the dissociation (separation) of a water molecule into a hydrogen ion and a hydroxide ion:
H2O 
H+ + OH−
Although the dissociation of water is reversible and statistically rare, it is exceedingly important in the chemistry of life. Hydrogen and hydroxide ions are very reactive. Changes in their concentrations can drastically affect a cell's proteins and other complex molecules.