【Daily Question】Chemical Analysis Edition, 2021.12.8
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In the indirect iodine method, the correct procedure is as follows: A. Shake rapidly while titrating. B. Add an excess of KI, and carry out the titration at room temperature away from direct sunlight. C. Perform the titration at a constant temperature of 70–80°C. D. Add the starch indicator at the beginning of the titration. B
It should be B; CD is definitely wrong. As for A, shaking it rapidly can cause iodine to evaporate during the early stages of titration, so that’s also incorrect.