Abstract Titration curve is an important part of titration analysis principle. It shows the change of the nature of the equilibrium system in the process of titration,and the information of the stoichiometric point and the titration jump can be obtained, so as to guide the accurate titration and indicator selection. The titration curve equation is the relationship between the certain nature X (e.g. pH) of the system and the titration fraction a (or the titrant volume V)in the titration process, and after analyzing the equation the expression of the function X=f(a) can be obtained. For some complex systems, it is difficult to deduce the function X=f(a), but in most cases the inverse function a=g(X) is easier to deduce and the expression is more concise. In this paper, the equations of acid-base, coordination, redox and precipitation titration curves are systematically summarized, and the function X=f(a) or inverse function a=g(X) under different conditions are deduced, which expands the content of the textbook. According to the function, the titration curve can be directly plotted with Origin by function plotting, which is convenient and fast without producing the data points. The high-precision titration curve can be obtained by adding data points when plotting with the inverse function, and the information of the stoichiometric point and the titration jump can be found directly from the titration curve.
CHI Quan, WANG Xian. Plotting Titration Curves Accurately with Origin Using Titration Curve Equations[J]. Chinese Journal of Chemical Education, 2020, 41(2): 21-27.
