A

Amphiprotism

e.g., HS⁻ + H₂O ⇌ H₂S + OH⁻ or HS⁻ + H₂O ⇌ H₃O⁺ + S²⁻
Quick Reference
Formula / Notatione.g., HS⁻ + H₂O ⇌ H₂S + OH⁻ or HS⁻ + H₂O ⇌ H₃O⁺ + S²⁻
Also Known AsAmphoterism (related), amphiprotic substance, ampholyte, zwitterion-forming species

What is Amphiprotism?

Amphiprotism describes the ability of a substance to act as either a proton donor (acid) or a proton acceptor (base) depending on the reaction conditions. Water is the most common amphiprotic substance, acting as an acid with strong bases and as a base with strong acids. Other amphiprotic species include amino acids and the bicarbonate ion.

Formula & Notation

e.g., HS⁻ + H₂O ⇌ H₂S + OH⁻ or HS⁻ + H₂O ⇌ H₃O⁺ + S²⁻

Other Names / Synonyms: Amphoterism (related), amphiprotic substance, ampholyte, zwitterion-forming species

Properties & Characteristics

Amphiprotism is the property of a substance to act as either a proton donor (Brønsted acid) or a proton acceptor (Brønsted base) depending on the reaction conditions. Amphiprotic species contain at least one ionisable proton and also carry a lone pair able to accept a proton. Water is the classic amphiprotic substance (autoionisation: 2H₂O ⇌ H₃O⁺ + OH⁻). Other examples: HS⁻, HCO₃⁻, HPO₄²⁻, amino acids.

Uses & Applications

Amphiprotic species are critical in buffer systems and in biological fluids where they maintain pH homeostasis. Amino acids as amphiprotic compounds act as biological buffers. Understanding amphiprotism guides titration analysis and the design of amphoteric catalysts.

Safety Information

Amphiprotic substances vary widely in hazard. Strong amphiprotic acids (H₂SO₄ first dissociation) are corrosive. Common biological amphiprotic species (amino acids, bicarbonate) are generally safe. Follow standard laboratory safety for handling acidic or basic solutions.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Amphiprotism
Formula e.g., HS⁻ + H₂O ⇌ H₂S + OH⁻ or HS⁻ + H₂O ⇌ H₃O⁺ + S²⁻
Synonyms Amphoterism (related), amphiprotic substance, ampholyte, zwitterion-forming species

Frequently Asked Questions

Amphiprotism describes the ability of a substance to act as either a proton donor (acid) or a proton acceptor (base) depending on the reaction conditions. Water is the most common amphiprotic substance, acting as an acid with strong bases and as a base with strong acids. Other amphiprotic species include amino acids and the bicarbonate ion.

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