Acid salt

An acid salt is an ionic compound formed by partially neutralizing a polyprotic acid, leaving one or more replaceable hydrogen atoms in its anion.

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Polyprotic acid: An acid that can donate more than one proton per molecule. Acid salts form when only some of this acid’s protons are neutralized.
Phosphoric acid: A triprotic inorganic acid with formula H₃PO₄. Its three ionizable protons allow several distinct acid salts to form.
Baking powder: A dry leavening mixture that releases carbon dioxide when its acidic and basic ingredients react. Acid salts such as monocalcium phosphate supply controlled acidity in some baking powders.
Normal salt: A salt in which all replaceable acidic hydrogens of the parent acid have been replaced by cations. Unlike an acid salt, a normal salt has no acidic hydrogen remaining in its anion.
Conjugate base: The species formed when an acid donates a proton. An acid-salt anion is a partially deprotonated form of its parent acid.
Dihydrogen phosphate: The H₂PO₄⁻ anion, formed when phosphoric acid loses one proton. It is the acidic anion in salts such as sodium dihydrogen phosphate.
Sodium dihydrogen phosphate: The ionic compound NaH₂PO₄, containing the dihydrogen phosphate anion. It is used in buffers, food processing, and some pharmaceutical formulations.
Basic salt: A salt formed by incomplete neutralization of a base, retaining hydroxide or other basic groups. Basic salts retain basic groups, whereas acid salts retain acidic hydrogen in anions.
Neutralization: A reaction in which an acid and a base form water and a salt, or transfer protons. Partial neutralization leaves acidic hydrogen atoms in the resulting anion.
Hydrogen phosphate: The HPO₄²⁻ anion, formed when dihydrogen phosphate loses a proton. It retains one acidic hydrogen and forms salts such as disodium hydrogen phosphate.