Question

why it is advice that the iodised salt should be stored in airtight container

Answer 1

Storing iodated salt involves a few precautions. The iodine in the salt can be destroyed by prolonged exposure to direct sunlight and moisture. Therefore, store the salt in an air tight container made of plastic, wood, glass or clay, with a well-fitting lid. Make sure you consume iodated salt as early as possible.

Answer 2

it is advice that the iodised salt should be contain in airtight container becoz it get moist by reacting with oxygen.
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