Why is Starch used in an indicator in the titration of iodine with Sodium Sulphate?

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Why is Starch used in an indicator in the titration of iodine with Sodium Sulphate?

2006-11-02 12:06:39 · 2 answers · asked by Stevie B 2 in Science & Mathematics ➔ Chemistry

2 answers

Starch forms a blue-black complex with iodine or triiodide. As the Sodium sulfate reacts with the iodine, the color becomes clear.

This is called a visual indicator.

2006-11-02 12:33:49 · answer #1 · answered by Richard 7 · 65⤊ 0⤋

Iodine is an indicator for presence of starch, it turns blue-black when starch is present. Thats the reason for its use.

2006-11-02 12:53:14 · answer #2 · answered by Fatima A 3 · 0⤊ 0⤋