Title: Potassium Biphthalate
CAS Registry Number: 877-24-7
CAS Name: Phthalic acid potassium acid salt
Additional Names: potassium acid phthalate; potassium hydrogen phthalate; acid potassium phthalate
Molecular Formula: C8H5KO4
Molecular Weight: 204.22
Percent Composition: C 47.05%, H 2.47%, K 19.15%, O 31.34%
Line Formula: HOOCC6H4COOK
Literature References: Prepd by half-neutralization of a phthalic anhydride soln: F. J. Welcher, Organic Analytical Reagents vol. 2 (Van Nostrand, New York, 1947) pp 75-79.
Properties: Orthorhombic crystals, stable in air. d425 1.636. Acid reaction; pH of 0.05M aq soln at 25° = 4.005 (glass electrode). Sol in about 12 parts cold water, 3 parts boiling water; slightly sol in alcohol.
Density: d425 1.636
Use: As primary standard for preparing volumetric alkali solns, also as a buffer in pH determinations. |