What is the titrant used for amperometric titration of chlorine?

In amperometric titration for determining chlorine levels, phenylarsine oxide (POA) serves as the titrant. Using POA, a known concentration of the titrant is introduced to chemically react with the chlorine in the sample. The amperometric method measures the current change that occurs during the reaction, allowing for precise quantification of the chlorine concentration present.

This technique is valuable because it provides a direct measure of chlorine levels and is less subject to interference compared to other methods. The choice of phenylarsine oxide is particularly important as it reacts specifically with chlorine species, facilitating accurate results in various sample types.

The other options, while relevant in different contexts, do not serve effectively as titrants in amperometric titrations specifically for chlorine detection, which focuses on the unique properties of POA. Sodium thiosulfate is often used in iodometric titrations, potassium permanganate is commonly used in redox reactions but is not specific for chlorine, and hydrochloric acid functions primarily as a strong acid but does not have the reactive characteristics needed for this procedure.