Potassium hydrogen phthalate

Properties:
Potassium hydrogen phthalate is an acid salt of the organic aromatic acid phthalic acid, a colorless monoclinic crystal or white crystalline powder. It is stable in air, soluble in water, and slightly soluble in alcohol. It is soluble in approximately 12 parts cold water and 3 parts boiling water, and slightly soluble in ethanol. The solution is acidic. The pH of a 0.05 mol/L aqueous solution at 25°C is 4.005.

Applications:
Potassium hydrogen phthalate is readily purified by recrystallization. It is anhydrous, non-hygroscopic, easy to store, and has a large equivalent. It is commonly used for the standardization of sodium hydroxide standard solutions; it can also be used for the standardization of perchloric acid in acetic acid solutions (using methyl violet as an indicator).

Uses:
Used as a sirens for fireworks.

Uses:
Used as an analytical reagent and buffer.