Linked from
The 10 pages that link to Hydrogen ion, each with the reason it gives.
Gastric acidRelated: Its concentration gives gastric contents their acidity.
AcidityRelated: Hydrogen-ion concentration underlies the conventional pH measure of acidity.
Half-reactionRelated: H⁺ balances hydrogen and charge when half-reactions are balanced in acid.
Wine acidityBroader topic: Its activity, rather than total acid alone, underlies wine pH.
Acid saltRelated: The retained hydrogen in an acid-salt anion can be released as a proton.