An iron nail is sealed in a stoppered tube containing anhydrous calcium chloride. Why does this nail not rust?

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Question

An iron nail is sealed in a stoppered tube containing anhydrous calcium chloride. Why does this nail not rust?

Accepted Answer

The calcium chloride absorbs the water vapour, so no water is present — Award 1 mark. Air is still in the tube, so this arrangement tests whether water alone is required and shows that it is.

Answer

The stoppered tube is held at a very low pressure

Answer

Calcium chloride reacts with the oxygen and removes it

Answer

The calcium chloride absorbs the water vapour, so no water is present

Answer

The nail becomes coated in a layer of calcium

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