Potassium bisulfate is a chemical compound of the formula KHSO₄. This compound is commonly used in the conversion of tartrates to bitartrates in wine. Potassium bisulfate is also used as a disintegrating agent in analytical chemistry.

A solution of potassium bisulfate behaves like if the two congeners (K2SO₄ and H2SO₄) were side by side uncombined. Adding ethanol to a solution of potassium bisulfate precipitates out sulfate.

Sodium bisulfate is produced by two methods. One method involves mixing stoichiometric quantities of sodium hydroxide and sulfuric acid which react to form sodium bisulfate and water.

NaOH + H₂SO₄ NaHSO₄ + H₂O

A second production method involves reacting sodium chloride (salt) and sulfuric acid at elevated temperatures to produce sodium bisulfate and hydrogen chloride gas

NaCl + H₂SO₄ ? NaHSO₄ + HCl

The liquid sodium bisulfate is sprayed and cooled so that it forms a solid bead. The hydrogen chloride gas is dissolved in water to produce hydrochloric acid as a useful byproduct of the reaction.