Sodium bisulfate, also known as sodium hydrogen sulfate, is the sodium salt of the bisulfate anion, with the molecular formula NaHSO₄. Sodium bisulfate is an acid salt formed by partial neutralization of sulfuric acid by an equivalent of sodium base, typically either in the form of sodium hydroxide or sodium chloride. It is a dry granular product that can be safely shipped and stored. The anhydrous form is hygroscopic. Solutions of sodium bisulfate are acidic, with a 1M solution having a pH of < 1.