Question

Why food items like chips are sold in airtight packets?

Answer 1

Chips are sold in airtight packs filled with nitrogen to prevent rancidity.Rancidity is the oxidation of oils and fats which changes the taste and smell of the food

Answer 2

When food items comes into air,their oxidation chances are more.Oxidation can make food(oily food like chips) stale,smelly,unhealthy and poisonous too.
To prevent this oxidation they are sold in air tight container and that is not air tight surely.Nonreactive gases(like nitrogen) is given inside it as it prevents both air contact and oxidation.
Reason to use Nitrogen is,it has purely half filled orbital(3 electrons in p orbital and p orbital contains total 6 electrons in 3 sub orbitals).So nonreactive then other gases,which never happens in case of Oxygen.

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