question_answer 42)

  Which of the following gases can be used for storage of fresh sample of an oil for a long time? (a) Carbon dioxide or oxygen     (b) Nitrogen or oxygen (c) Carbon dioxide or helium      (d) Helium or nitrogen

Answer:

  (d) Helium and nitrogen both the gases provide inert atmosphere. When the packed food is surrounded by unreactive gas (nitrogen or helium), there is no oxygen (or air) to cause its oxidation and make it rancid.