- Synonyms: Potassium biphthalate, Phthalic acid monopotassium salt, KHPr- C8H5KO4r- M = 204,22 g/molr- CAS [877-24-7]r- EINECS-No.: 212-889-4r- Solub. in water: (20 ºC): 80 g/lr- Melting point: 295 - 300 ºCr- LD 50 (oral, rat): > 3200 mg/kgr- Tariff number: 2917 39 80 80r- Applications: analytical chemistry, titrant in volumetric analysis (bases), in buffer solutions.rrSPECIFICATIONSrassay (acidimetric, on dried sample): 99,95 - 100,05 %ridentity (IR-spectrum): passes testrinsoluble in water: max. 0,005 %rpH (0,05 mol/l, H2O, 25 °C): 4,00 - 4,02rchlorine compounds (as Cl): max. 0,003 %rchlorides (Cl): max. 0,002 %rtotal nitrogen (as N): max. 0,001 %rheavy metals (as Pb): max. 5 ppmriron (Fe): max. 5 ppmrsodium (Na): max. 0,005 %rsulphur compounds (as S): max. 0,002 %rrThis standard solution is traceable to Standard Reference Material from NIST. r