What ionic species is primarily detected in a coulometric chloride titration?

In a coulometric chloride titration, the primary ionic species that is detected is the chloride ion. This method involves the electrochemical generation of silver ions from an electrolyte solution, which then reacts quantitatively with the chloride ions present in the sample. The amount of silver ions produced corresponds directly to the amount of chloride ions being titrated.

Coulometric titration is particularly advantageous because it allows for very accurate measurements, as the total amount of chloride can be determined from the charge passed during the electrochemical reaction. The principle relies on Faraday's laws of electrolysis, which relate the amount of substance transformed to the total electric charge passed through the solution. Therefore, as chloride ions react with the generated silver ions, they are the direct analyte being measured, making them the primary ionic species detected in this titration method.

Other ions such as silver ions, acetic acid, and ammonium ions do not represent the main analyte being measured in this specific test; rather, they may be involved in the process in indirect ways but do not lead to the determination of chloride concentration.