Final answer:
The electrode mentioned in the reference is a glass electrode used for pH measurements, characterized by a thin glass membrane. It is not explicitly about electrodes applied to skin, which may differ in design and function for other applications.
Step-by-step explanation:
The electrode applied directly to the client's skin in electrochemical measurements is not explicitly described in the reference provided. However, the reference mentions a glass electrode, which is a type of sensor used to measure pH levels.
In this glass electrode, an internal Ag/AgCl electrode is immersed in a 1 M HCl solution and separates from the sample solution by a very thin glass membrane. The potential of this electrode depends on the hydrogen ion (H+) concentration in the sample, which is related to the pH.
This suggests that in contexts related to pH measurement, the sensor electrode, which could be analogous to the electrode applied to the client's skin, is the glass electrode with a thin glass membrane. On the other hand, for other types of electrochemical measurements, different electrodes may be used that are specifically designed to be in direct contact with the skin, but these are not described in the given reference.