Thermodynamic study of corrosion of zinc metal in dioxan-water mixture in hydrochloric acid

The corrosion of pure zinc in 0.1 N HC1 has been investigated in aquo-organic solvent media in the temperature range of 25-50°C and in 0-70% by volume organic cosolvent. The data has been analysed to obtain kinetic activation parameters for reaction in corresponding mixtures. The determined isokinetic temperature indicates that the reaction is enthalpy controlled. The corrosion currenti[corr]is correlated to the dielectric constant [D]. Medium effects on reaction rates and mechanisms are briefly discussed

Thermodynamic studies of some dicarboxylic acid dissociation reactions in 10 [V/V] dioxane

PK[1]and pK[2]values of some dicarboxylic acids [succinic, trataric, malonic, maleic and phthalic] have been determined in 10% [v/v] dioxane at different temperatures [30-60°C] using e.m.f. method. The thermodynamic properties [delta G[o], delta H[o]and delta S[o]]for the first and the second dissociation reactions were computed. delta H[o-]delta S[o]as well as delta S[o] delta G[o] correlations among the studied dicarboxylic acids are examined. The negative delta -S[o] values for the first dissociation reaction which follow the order, maleic < tartaric < succinic < phthalic has been discussed in the light of solute-solvent interactions