What definition of acids and bases emphasizes the role of protons?
This applies for Bronsted-Lowry acids and bases.
- A Bronsted-Lowry acid is defined as a proton donor.
Here, it's clear that sulfuric acid (
- A Bronsted-Lowry base however, is a proton acceptor .
Here, it is clear that ammonia (
- Now if you look closely at the first equation, involving sulfuric acid, you'll find that water is acting as a base to form
#H_3O^+#from #H_2O#. It accepted a proton.
And if you look at the second equation, involving ammonia, water is acting as an acid and forming
Thus, water can act as both , an acid and a base. We say that water is amphoteric .