The standard second ionization constant of sulphuric acid, K 2 and the standard association constant of ion pair [MgSO 4] 0, K D, in 0.05 molar fraction i PrOH water mixture at five temperatures, from 278 15 to 318 15 K were determined from precise emf measurements of different cells without liquid junction. The results have been discussed in term of the solute solvent interaction and have been compared with those results in water.
