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

Explanation

Auto-protolysis' means self-ionisation of water, and can be represented as:

Water is atphoteric in nature, i.e., it reacts both with acids and bases. It acts as an acid towards bases stronger than itself and as a base towards acids stronger than `H_(2)O` itself.
`{:(H_(2)O_(1),+,NH_(3(aq)),to,NH_(4(aq))^(o+),+,overset(o-)(O)H_(aq)),("Acid"_(1),,"Base"_(2),,"Acid"_(2),,"Base"_(2)),(H_(2)O_(1),+,H_(2)S_((aq)),to,H_(3)O_((aq))^(o+),+,HS_((aq))^(Θ)),("Base"_(1),,"Acid"_(2),,"Acid"_(1),,"Base"_(1-)):}`