Question

Why are the bags of potato chips usually flushed with nitogen gas ?

Answer 1

The bags of potato chips are usually flushed with nitrogen gas because it prevents the potato chips from oxidising. When fats and oils are oxidised, they become rancid and their smell and taste change. Food items containing oil and fat are flushed with nitrogen to prevent rancidity.

So they are usually flushed with nitrogen gas.

Hope it helps

Answer 2

The bags of potato chips are  usually flushed with nitrogen gas.
When the packed food is surrounded by an un-reactive gas nitrogen  , there is no oxygen [ of air ] to cause its oxidation and make it rancid.
The manufacturers of potato chips [ and other similar food products ] fill the plastic bags containing chips with nitrogen gas to prevent the chips from getting oxidised and turn rancid. [ unpleasant smell and taste ]