Sodium hydrogen sulfate, also known as sodium bisulfate, is a chemical compound with the formula NaHSO4. It appears as a white, crystalline solid and is commonly used as a pH regulator in swimming pools and as a cleaning agent. It is soluble in water, where it dissociates into sodium ions and hydrogen sulfate ions. This compound is also utilized in various industrial processes, including the production of sulfuric acid and as a food additive. In the food industry, it serves as a preservative and acidity regulator. Sodium hydrogen sulfate is generally considered safe when used appropriately, but it can be corrosive in concentrated forms.