Which method is listed as another approach for the modified Winkler method?

Which method is listed as another approach for the modified Winkler method?

• A. EDTA Titration Method
• B. Modified EDTA Titration Method
• C. Modified Mohr Method
• D. Iodometric Method

Answer: (D)

Dissolved oxygen is determined with the Winkler approach by generating iodine from the sample’s oxygen content and then measuring that iodine. The iodometric method is the route that directly quantifies the iodine produced in this reaction, typically by titrating with a thiosulfate solution and using starch as an indicator to detect the endpoint. This approach aligns with how the Winkler reagents convert oxygen into an iodine signal, giving a measure of DO in the sample. The other methods listed aren’t used for Winkler DO determinations. EDTA titration methods are for complexometric analysis of metal ions and hardness, not for measuring iodine or oxygen. The Modified Mohr method is an argentometric titration used for chlorides, not for the iodine chemistry central to the Winkler DO determination.

Dissolved oxygen is determined with the Winkler approach by generating iodine from the sample’s oxygen content and then measuring that iodine. The iodometric method is the route that directly quantifies the iodine produced in this reaction, typically by titrating with a thiosulfate solution and using starch as an indicator to detect the endpoint. This approach aligns with how the Winkler reagents convert oxygen into an iodine signal, giving a measure of DO in the sample.

The other methods listed aren’t used for Winkler DO determinations. EDTA titration methods are for complexometric analysis of metal ions and hardness, not for measuring iodine or oxygen. The Modified Mohr method is an argentometric titration used for chlorides, not for the iodine chemistry central to the Winkler DO determination.