The adsorption of bromide ion on liquid gallium from aqueous
solutions of NaBr + HBr of concentrations
ranging from 0.02 to 1.99 M was determined on the basis of capacitive
charge measurements carried out by
a computerized chronocoulometric technique. This adsorption is
parametrized by the use of the virial isotherm
corrected for the potential difference across the diffuse layer.
The resulting adsorption behavior has several
features in common with chloride, bromide, and iodide adsorption on
mercury. These general features are
interpreted on the basis of a molecular model that accounts for the
local potential at the position of an adsorbed
anion created by the surrounding anions as well as by the water
dipoles. The fundamental role played by the
mutual interactions among the adsorbed anions, the adsorbed water
dipoles, and the inhomogeneous electron
gas, the latter treated on the basis of a simple one-parameter jellium
model, is pointed out.