Why is it important to use the Scientific Method?

Azide-Winkler Method! could you explain to me why this method is use to measure the dissolves oxygen?

• i do not understand why this kind of method can use to measure the dissolves oxygen? why we should add manganase sulfate solution, then add akaline-iodine solution, and the sulphuric acid; after that, sodium thiosulphate solution have use to titrate the solution(also have add some starch solution)?

• Answer:

  The azide-winkler method is described as the most accurate method to ascertain the dissolved oxygen within a liquid sample. The main purposed of adding Manganese sulfate and the alkaline is to generate Manganese Hydroxide which will react with Oxygen. As the Manganese Oxide-Hydroxide compound is not stable, Potassium Iodide is used to react with it and under acidic conditions would result in Iodine (I2) being generated. The amount of Iodine generated corresponds to the amount of oxygen in the liquid sample. The titration is really to find out how much Iodine is present and from there infer how much oxygen was present.