IUPAC-NIST Solubility Database
NIST Standard Reference Database 106


Glass Ball as Bullet Solubility System: Potassium formate with Potassium hydroxide and Water

Components:
   (1) Potassium formate; KCHO2; [590-29-4]  NIST Chemistry WebBook for detail
   (2) Potassium hydroxide; KOH; [1310-58-3]  NIST Chemistry WebBook for detail
   (3) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Bianco, P.; Haladjian, J.; Sabbah, R., Bull. Soc. Chim. Fr. 7, 2301 (1969).

Variables:

   Concentration = Composition at 25 ºC

Prepared By:
   Chr. Balarew and St. Trendafilova

Experimental Data:   (Notes on the Nomenclature)
(Please see footnotes following the table(s).)
  
Solubility values in the KCHO2-KOH-H2O system at 25 °C.
Chemical1PhaseMass Fraction w1Chemical2Mass Fraction w2m2 [mol kg-1]aChemical3Mass Fraction w3m3 [mol kg-1]aSolid Phase(s)b
K2OLiquid1.32KOH1.571.28KCHO276.6441.82A
K2OLiquid3.88KOH4.623.44KCHO271.4135.42A
K2OLiquid13.42KOH15.989.12KCHO252.7920.10A
K2OLiquid18.78KOH22.3612.16KCHO244.8816.29A
K2OLiquid29.29KOH34.8817.23KCHO229.049.57A
K2OLiquid34.87KOH41.5320.70KCHO222.727.56A
K2OLiquid38.67KOH46.0521.01KCHO214.894.53A
K2OLiquid40.45KOH48.1721.48KCHO211.863.53A+B
K2OLiquid42.67KOH50.8121.09KCHO26.251.73B
K2OLiquid44.89KOH53.4620.47KCHO20.00.0
K2OLiquid45.24KOH53.8520.80KCHO20.00.0
Notes:
   a  These values were calculated by the compilers.
   b  The solid phases are: A = KCHO2; B = KOH•2H2O.

Method/Apparatus/Procedure:
   The isothermal method was used. The concentration of potassium formate was determined by potentiometric titration. The solid phases were identified thermogravimetrically and by the Schreinemakers' method.

Source and Purity of Materials:
   Merck p.a. grade formic acid was used. The KOH was Riedel de Haen p.a. grade. The water was de-ionized.

Estimated Errors:

   Temperature: Accuracy of temperature measurement was ± 0.05°C. Solubility error was ± 1%.