Study of apparent molal volume and viscosity of mutual citric acid and disodium hydrogen orthophosphate aqueous systems

Fundamental properties, density (r) and viscosity (h), of citric acid (CA) and disodium hydrogen orthophosphate (DSP) at various strengths were obtained at different temperatures. The p and n values were used to determine apparent molal volumes and viscosity of systems. The p Vf and n values were regressed against molality m for p0, n0 and V0 the limiting constants at infinite dilution (m →0) for ionic and molecular interactions. The p0 and V 0 f of aq. acids are higher than those of aq. DSP and the viscosity of DSP is higher than that of aq. CA. Examination of p0 and V 0 f functions indicates that mutual compositions of CA and DSP counterbalance concentration and temperature effects on pH in bioprocesses.