IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Lead formate with Sodium hydroxide and Water

Components:
   (1) Lead formate; Pb(CHO2)2; [811-54-1]  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:
   Gyunner, E.A.; Melnichenko, N.D.; Yakhkind, N.D.; Velmozhnii, I.S.; Katseva, G.N., Zh. Neorg. Khim. 24, 2172-2175 (1979).

Variables:

   Concentration = Composition at 20 ºC

Prepared By:
   Chr. Balarew and St. Trendafilova

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

Ratio OH^-: Pb²⁺ in the liquid phase in the Pb(CHO₂)₂ - NaOH - H₂O system at 20 °C.
Chemical₁	Phase	10⁰ * Mole Fraction₁	Chemical₂	Mole Fraction₂	Solid Phase(s)^a
NaOH	Liquid	10.0	Pb(CHO2)2	---	A
NaOH	Liquid	15.0	Pb(CHO2)2	---	A
NaOH	Liquid	20.0	Pb(CHO2)2	---	A
NaOH	Liquid	25.0	Pb(CHO2)2	---	A
NaOH	Liquid	30.0	Pb(CHO2)2	---	A
NaOH	Liquid	33.3	Pb(CHO2)2	---	A
NaOH	Liquid	40.0	Pb(CHO2)2	---	A
NaOH	Liquid	45.0	Pb(CHO2)2	---	A
NaOH	Liquid	50.0	Pb(CHO2)2	1.70	A
NaOH	Liquid	55.0	Pb(CHO2)2	1.67	A
NaOH	Liquid	60.0	Pb(CHO2)2	1.69	A
NaOH	Liquid	62.5	Pb(CHO2)2	1.66	A
NaOH	Liquid	65.0	Pb(CHO2)2	1.84	A
NaOH	Liquid	66.7	Pb(CHO2)2	2.00	B
NaOH	Liquid	70.0	Pb(CHO2)2	2.01	B
NaOH	Liquid	75.0	Pb(CHO2)2	2.02	B
NaOH	Liquid	80.0	Pb(CHO2)2	2.02	B
NaOH	Liquid	85.0	Pb(CHO2)2	2.02	B
NaOH	Liquid	90.0	Pb(CHO2)2	2.03	B

Notes:
   ^a  The solid phases are: A = Pb₃(OH)₅(CHO₂); B = Pb(OH)₂.

Method/Apparatus/Procedure:
   The system is studied by the method of physico-chemical analysis. After attaining the equilibrium, the residue concentrations of Pb²⁺ and OH^- are measured and also refractive index (n) of the liquid phases. The methods of measurements are according to Ref. 1.

Source and Purity of Materials:
   The lead formate is obtained from lead carbonate and formic acid. The obtained product is twice recrystallized.

Estimated Errors:

   Temperature: t = ± 0.05 °C.

References:
   ¹ E. A. Gyunner, N. D. Melnichenko, N. D. Yakhkind, G. N. Bobrishev, and G. N. Katseva, Zh. Neorg. Khim. 23, 711 (1978).