Potassium Phosphate also known as Dipotassium hydrogen phosphate is a potassium salt that is the dipotassium salt of phosphoric acid. It has a role as a buffer. It is a potassium salt and an inorganic phosphate. Dipotassium phosphate (K2HPO4) is a highly water-soluble salt often used as a fertilizer and food additive as a source of phosphorus and potassium as well as a buffering agent.