Amphiprotic

Definition

An amphiprotic substance can act as both a proton donor (acid) and a proton acceptor (base) depending on the chemical environment. Water is a common example of an amphiprotic substance.

5 Must Know Facts For Your Next Test

1. Amphiprotic substances can participate in both acid and base reactions.
2. In water, amphiprotic substances can either donate or accept a proton to form H3O+ or OH- respectively.
3. The concept of amphiprotic is central to understanding Brønsted-Lowry acids and bases.
4. Examples of amphiprotic substances include water (H2O), amino acids, and hydrogen carbonate ion (HCO3-).
5. The ability to be amphiprotic is determined by the presence of a transferable hydrogen atom and the ability to accept one.

Review Questions

• What characteristic allows a substance to be classified as amphiprotic?
• Give two examples of amphiprotic substances.
• How does an amphiprotic substance behave differently in acidic versus basic environments?

Related terms

Brønsted-Lowry Acid: A species that donates a proton (H+) in a chemical reaction.

Brønsted-Lowry Base: A species that accepts a proton (H+) in a chemical reaction.

Amphoteric: A broader term for substances that can react with both acids and bases, not limited to just transferring protons.