What do you understand by the term 'auto-protolysis' of water? What is its significance?

(N/A) Auto-protolysis refers to the self-ionization of water,where water molecules react with each other to form ions.
It is represented by the equation:
$H_2O_{(l)} + H_2O_{(l)} \rightleftharpoons H_3O^{+}_{(aq)} + OH^{-}_{(aq)}$
Significance:
Due to auto-protolysis,water exhibits amphoteric nature,meaning it can act as both an acid and a base.
It acts as a base when reacting with acids stronger than itself and as an acid when reacting with bases stronger than itself.
Examples:
$1$. As an acid: $H_2O_{(l)} + NH_{3(aq)} \longrightarrow NH_{4(aq)}^{+} + OH^{-}_{(aq)}$
$2$. As a base: $H_2O_{(l)} + H_2S_{(aq)} \longrightarrow H_3O^{+}_{(aq)} + HS^{-}_{(aq)}$