Which kind of compound increases the hydrogen ion concentration in a solution?

A.) A substance that releases hydroxide ions

B.) An acid

C.) A base

D.) A substance that donates electron pairs

B. An acid

Acids increase the number of hydrogen ions, which are symbolized as H + in chemical formulas, in a solution. Stronger acids more readily donate their hydrogen ions, creating an unequal balance of ions. One example is hydrochloric acid, written as HCl, which completely dissociates in solution into hydrogen and chloride ions.