pH Titrations

These cover a range of applications from simple titrations to pH control to the determination of Ka and Ksp of acids and salts. Many of the setups proposed are made quite simple by incorporating the FS-522 interface unit and suitable accessories, such as drop dispensers and drop counters. References are arranged oldest to newest.

An experiment for the pH meter
Robert L. Pecsok
J. Chem. Educ., 1951, 28 (5), p 252
This is the original article on the analysis of phosphoric acid with a titration curve and the analysis of a mixture of phosphates.

Determination of the ionization constant of sparingly soluble weak acids: An experiment for analytical-organic courses
Chris E. Baldwin and James S. Evans
J. Chem. Educ., 1974, 51 (3), p 205

Potentiometric titration of acidic and basic compounds in household cleaners
Van T. Lieu and Gene E. Kalbus
J. Chem. Educ., 1988, 65 (2), p 184

A pH-monitoring and control system for teaching laboratories
Jorge G. Ibáñez , Luis Tavera , Alberto Rodriguez and Enrique Gomez del Campo
J. Chem. Educ., 1990, 67 (3), p A74

MicroLab, with a pH probe and its solenoid controlled drop dispenser would be particularly easy to use for pH control. This article gives you some ideas as to why you might wish to consider doing this.

Chemical equilibrium: VII. pH approximations in acid-base titrations
Adon A. Gordos
J. Chem. Educ., 1991, 68 (9), p 759

Potentiometric Measurement of Transition Ranges and Titration Errors for Acid/Base Indicators
Paul A. Flowers
J. Chem. Educ., 1997, 74 (7), p 846

Potentiometric Measurement of Transition Ranges and Titration Errors for Acid/Base Indicators
Paul A. Flowers
J. Chem. Educ., 1997, 74 (7), p 846

The Henderson-Hasselbalch Equation: Its History and Limitations
Henry N. Po and N. M. Senozan
J. Chem. Educ., 2001, 78 (11), p 1499

Microscale pH Titrations Using an Automatic Pipet
Edward B. Flint , Carrie L. Kortz and Max A. Taylor
J. Chem. Educ., 2002, 79 (6), p 705

Instead of a 100uL pipet, why not consider the MicroLab precision drop dispenser, a ca. 35uL dispenser, to create the pH-volume titration curve? Then use the MicroLab software to create the 1st and 2nd derivative curves and the Gran Plot to compare end points by the various curves.

Determination of Acidity Constants by Gradient Flow-Injection Titration
Manuel E. Minas da Piedade , António C. L. Conceição
J. Chem. Educ., 2006, 83 (12), p 1853

This is a variation on a photometric titration using a pump instead of a drop dispenser or micropipet, following the color change of an indicator vs. time instead of vs. volume titrant. With the new software from MicroLab, we can monitor pH, drops (volume), and absorbance at a chosen wavelength simultaneously.

A Simple Determination of the Ag2O Solubility Product by Potentiometric Determinations of Both Ag+1 and OH–1
Frederick C. Sauls
J. Chem. Educ., Articles ASAP (As Soon As Publishable)
Publication Date (Web): August 14, 2013 (Laboratory Experiment)
DOI: 10.1021/ed300586g

Here is another example of how MicroLab makes this experiment easy. Instead of using two pH meters as suggested by the authors (one to measure the potential difference between the Ag electrodes and one to measure the pH), the pH of the solution can be measured at the FS522’s pH/ISE/redox input, and the mV can be read at the voltage input set to the appropriate range.