Write chemical reactions to show the amphoteric nature of water.
The amphoteric nature of water can be described on the basis of the following reactions:
1) Reaction with H2S
The reaction takes place as:
In the forward reaction, water molecule accepts a proton from hydrogen sulphide and hence water acts as a Lewis base.
2) Reaction with NH3
The reaction takes place as:
In the forward reaction, water donates its proton to ammonia molecule and hence in this case water acts as a Lewis acid.
3) Self-ionization of water
The auto-protolysis reaction of water molecule exhibit the amphoteric nature of water molecule that is the molecule of water can acts as an acid as well as a base.
The acid-base reaction can be written as:
Thus the above mentioned reactions depict the amphoteric nature of water molecule.