EFFECT OF TEMPERATURE ON THE DISSOCIATION COEFFICIENT OF ACETIC ACID

Abstract

This article is devoted to metrological study of acetic acid dissociation process at a temperature change in the range from 20 °C to 75 °C. The study considers methodology methods and presents their classification. The main experiments methodology is identified. The selected methods reflect the rapid determination of acidity using a portable pH meter. The concentration of working acid solution is 6 mol/l, from which a solution with a concentration of 1 mol/l is prepared. Nodal temperature points (four points in temperature range 20 °C – 75 °C) are chosen for measurements; 5 test samples of acetic acid are formed (С(HAc) = 1 mol/l); the analysis of measurements results at nodal points are carried out for the results accuracy on five experimental samples of acetic acid according to first and second order statistical moments; the characteristics of experimental data accuracy are evaluated. Acetic acid samples are brought to nodal points with a positive temperature gradient using a steam bath. The measurement error estimate is determined by the device accuracy class and is 0.32. The dissociation constant is determined from the obtained pH values. These determinations are carried out under condition of ensuring chemical equilibrium. The nature of dissociation constant temperature dependency is clearly non-linear.