Why are acids called proton donors?

Acids are substances that can donate H+ ions to bases. Since a hydrogen atom is a proton and one electron, technically an H+ ion is just a proton. So an acid is a "proton donor", and a base is a "proton acceptor". The reaction between an acid and base is essentially a proton transfer.

The relationship between acids and bases is more aggressive than the donor/acceptor terminology implies. Bases don't passively "accept" protons; they rip hydrogen ions from acids. Acids don't "donate" hydrogen ions; they surrender them.

Author: Fred Senese senese@antoine.frostburg.edu

General Chemistry Online! Why are acids called proton donors?

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Last Revised 08/17/15.URL: http://antoine.frostburg.edu/chem/senese/101/acidbase/faq/print-bronsted-definition.shtml