IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Sodium formate with Sodium hydroxide and Water

Components:
   (1) Sodium formate; NaCHO2; [141-53-7]  NIST Chemistry WebBook for detail
   (2) Sodium hydroxide; NaOH; [1310-73-2]  NIST Chemistry WebBook for detail
   (3) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Centola, G.P.; Rosso, E.R.; Mazzoccia, V.C., J. Chem. Eng. Data 25, 170-1 (1980).

Variables:

   Concentration = Composition at 21 ºC

Prepared By:
   Chr. Balarew and St. Trendafilova

Experimental Data:   (Notes on the Nomenclature)
(Please see footnotes following the table(s).)

Liquid phase composition of the NaCHO₂-NaOH-H₂O system at 21 °C.
Chemical₁	Phase	Mass Fraction w₁	m₁ [mol kg-1]^a	Chemical₂	Mass Fraction w₂	m₂ [mol kg-1]^a
NaOH	Liquid	0.0	0.0	NaCHO2	50.3	14.9
NaOH	Liquid	1.7	0.84	NaCHO2	47.3	14.0
NaOH	Liquid	3.7	1.82	NaCHO2	45.4	13.1
NaOH	Liquid	8.8	4.05	NaCHO2	36.9	9.99
NaOH	Liquid	9.9	4.53	NaCHO2	35.5	9.56
NaOH	Liquid	12.0	5.32	NaCHO2	31.6	8.24
NaOH	Liquid	16.0	6.93	NaCHO2	26.3	6.70
NaOH	Liquid	18.6	7.85	NaCHO2	22.2	5.51
NaOH	Liquid	21.5	9.06	NaCHO2	19.2	4.76
NaOH	Liquid	24.1	10.1	NaCHO2	16.6	3.93
NaOH	Liquid	32.4	13.6	NaCHO2	8.2	2.0
NaOH	Liquid	35.5	15.1	NaCHO2	5.6	1.4
NaOH	Liquid	52.1	27.2	NaCHO2	0.0	0.0

Notes:
   ^a  These values were calculated by the compilers.

Method/Apparatus/Procedure:
   Weighed amounts of NaOH and formic acid were dissolved in de-ionized water and placed in closed 250 cm³ flasks. The flasks were placed in a constant temperature bath. Equilibrium was reached in 6 h. Samples were removed after 24 h and analyzed. The sodium formate content was determined by adding excess KMnO₄ and titrating the excess iodometrically. NaOH was determined by titration with formic acid.

Source and Purity of Materials:
   Carlo Erba pure reagents were used.

Estimated Errors:

   Temperature: Accuracy of temperature measurement was ± 0.05°C.