Question

Principle of operation of ISE (ion-selective electrodes)?

a) Ion-selective electrodes measure electrical conductivity
b) Ion-selective electrodes use colorimetric reactions
c) Ion-selective electrodes detect mass changes
d) Ion-selective electrodes rely on spectrophotometry

Answer 1

Ion-selective electrodes operate on electrochemical principles, measuring specific ion concentrations in a solution by responding to the ion charge and changing their potential accordingly.

Step-by-step explanation:

The principle of operation of ion-selective electrodes (ISEs) is based on the electrochemical principle of selectively allowing ions through a channel based on their charge. ISEs are designed to measure the concentration of a specific ion in solution, with their potential changing in response to the ion concentration. They contain an internal reference electrode connected by an electrolyte solution to a sensor, such as a crystalline inorganic material or a membrane. For instance, a fluoride electrode uses a single crystal of Eu-dpedd LaF3 and responds to fluoride ions in solution. These electrodes do not measure electrical conductivity, use colorimetric reactions, detect mass changes, or rely on spectrophotometry, making option (c) incorrect for describing their operation.