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

Kinetics of oxidation of Benzoin by potassium bromate

The kinetics of oxidation of benzoin by bromate ion has been studied in acetic acid-water medium in presence of sulphuric acid. The effect of acidity on the rate of oxidation has been investigated by correlating the observed pseudo first order rate constant with the free hydrogen ion concentration [obtained from e.m.f.s. of a chemical cell comprising glass and calomel electrodes]. The order with respect to [H[+]] was found to be. one, different from that reported by Natarajan and Venkatasubramanian as three, who used sulphuric acid concentration as[H[+]],.which is incorrect especially in this medium of lower dielectric constant. Moreover, the experimentaly determined rate law takes a new form with the subsequent modifications of the proposed reaction mechanism. The extrathermodynamic analysis of reaction rate reveals that this reaction is an enthalpy cotrolled type