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Potassium dichromate solution is used to...

Potassium dichromate solution is used to test drunken driver. Discuss.

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Aqueous solution of potassium dichromate is orange. The driver is asked to breath into the solution. If the solution changes to green, the driver is in drunken state. This is because dichromate oxidises ethanol to acetic acid and itself is reduced to green chromic salt in solution.
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