Oil and fat containing food items are flushed with nitrogen. Why?

Explain the term 'Corrosion' with one example.

Which one is a chemical change: Rusting of iron or melting of iron?

The marble statues are often slowly corroded when kept in the open for a long time. Give a suitable reason.

Give reasons for the following:
$(i)$ Keeping food in airtight containers helps in preventing rancidity.

$A$ student has been collecting silver coins and copper coins. One day she observed a black coating on silver coins and a green coating on copper coins. Which chemical phenomenon is responsible for these coatings? Write the chemical name of black and green coatings.