Final answer:
The three basic types of CAC-A electrodes are SCE (Saturated Calomel Electrode), Glass electrode, and Ion-selective electrode, each with different structural features and functions in electrochemical measurements.
Step-by-step explanation:
The three basic types of CAC-A (Combined Alkali Cation-Antimony) electrodes are:
- SCE (Saturated Calomel Electrode): This is a reference electrode that includes a platinum wire inserted into a moist paste of liquid mercury and KCl (calomel; Hg₂Cl₂). The electrode is surrounded by an aqueous KCl solution that functions as a salt bridge.
- Glass electrode: Consists of an internal Ag/AgCl electrode that is immersed in a 1 M HCl solution. This solution is separated from the sample solution by a thin glass membrane. The potential of the electrode is dependent on the H* ion concentration of the sample.
- Ion-selective electrode: This electrode's potential depends on the concentration of a specific ionic species in the solution.
These electrodes are essential tools for measuring the electric potentials in various chemical solutions, significantly contributing to analytical chemistry and various electrochemical applications.