TEMPERATURE-DEPENDENCE OF THE DIFFUSION-COEFFICIENT OF SULFURIC-ACID IN WATER

The method of restricted diffusion has been applied to aqueous sulfuri c acid in order to determine differential diffusion coefficients spann ing the composition range from 0.5 to 5.5 M, at temperatures between 0 and 35 degrees C. Rayleigh interferometry was used for measuring conc entration differences with time. The following expression summarizes t he experimental data D=exp[C-0(1/T-1/298.15)]C-1 cm(2)/s where exp(-12 c(1/2))]-0.2977c+0.04164c(3/2)+0.02023c(2)} -exp(-12c(1/2))]-0.1107c+0 .2888c(3/2)-0.09151c(2)} and c is in mol/liter (M). The activation ene rgy of diffusion corresponds to the average value of the activation en ergy between solvent-anion and solvent-cation interactions.