Analytical data: Potentiometric study of the association constant of isothiocyanic acid.
The association constant of isothiocyanic acid, HNCS, has been determined potentiometrically and found to be 0.135 +/- 0.007 and 0.168 +/- 0.007 at ionic strengths (NaClO(4)) of 2.0 and 4.0M respectively. The indicator electrode was Hg(SCN)(2-)(4)/Hg. For accuracy and precision the metal phase was used in the form of a dropping electrode. Because the association constant is so low, liquid-junction potentials would cause significant errors, since a strong acid was added to the working solutions in the procedure, and an estimate of this effect was taken into account.
Neves
E A
EA
Instituto de Química da Universidade de São Paulo, São Paulo, Cx. Postal 20780, Brazil.
Angnes
L
L
Chierice
G O
GO
Mazo
L H
LH