Glass electrodes are good examples of ion selective electrodes because the glass membrane has selectivity for specific single or double-charged cations like hydrogen, sodium, silver, lead, and cadmium ions. The glass membrane also has excellent chemical durability and can operate in aggressive media. A common example is the pH glass electrode, which uses a glass membrane sensitive to hydrogen ions to measure pH.

1. explain why glass electrode is a good example of an ion selective electrode
Solution
Glass membranes are made from an ion-exchange type of glass (silicate or chalcogenide). This
type of ISE has good selectivity, but only for several single-charged cations; mainly H +
, Na +
,
and Ag +
. Chalcogenide glass also has selectivity for double-charged metal ions, such as Pb 2+
,
and Cd 2+
. The glass membrane has excellent chemical durability and can work in very
aggressive media. A very common example of this type of electrode is the pH glass electrode.
An ion-selective electrode ( ISE ), also known as a specific ion electrode ( SIE ), is a
transducer (or sensor) that converts the activity of a specific ion dissolved in a solution into an
electrical potential. The voltage is theoretically dependent on the logarithm of the ionic activity,
according to the Nernst equation. Ion-selective electrodes are used in analytical chemistry and
biochemical/biophysical research, where measurements of ionic concentration in an aqueous
solution are required.
A glass electrode is a type of ion-selective electrode made of a doped glass membrane that is
sensitive to a specific ion. The most common application of ion-selective glass electrodes is for
the measurement of pH. The pH electrode is an example of a glass electrode that is sensitive to
hydrogen ions. Glass electrodes play an important part in the instrumentation for chemical
analysis and physico-chemical studies. The voltage of the glass electrode, relative to some
reference value, is sensitive to changes in the activity of certain type of ions.