Use of Potentiometric:

You have seen that potentiometric methods mostly include two major types of analysis. First one being direct measurement of an electrode potential from which the activity (or concentration) of an active ion may be derived. The other type involves, measuring the changes in the electromotive force (emf) brought about by the addition of a titrant to the sample.

The principle of potentiometry can be applied to measure the emf, in terms of pH unit on pH scale by suitable modifying the common voltmeter to high input impedance mV meter. The acid-base titrations, involving measurement of change in pH to detect the end point, can be termed as pH metry instead of potentiometry.

Objectives of developing pH metry lies in recognising the importance of pH, the very important test performed in studying chemical, biochemical, microbiological processes involved in various unit operations and processes in small to large scale organization productions. Within each phase of water and wastewater treatment processes, that is. in acid-base neutralization, precipitation, water softening, coagulation in the field of both production and environmental protection technologies, all these processes are carried out at specific range.

Objectives

After studying this unit, you should be able to:

• draw and level a glass electrode,
• the Nernst equation will be write for a glass electrode,
• describe how the pH meter can be used to measure the pH, and
• describe how the pH data can be used to determine the equivalence point in acid base titrations, and
• make a list of the applications of ion-selective electrodes