Airbags work on the principle of a chemical reaction triggered by the impact producing a gaseous product that causes a sudden volume change. Which one among the following chemical conversions is responsible for this ?

Which one of the following processes involves chemical reaction?

Which one among the following is an example of oxidation reaction?

An iron nail dipped in copper sulphate solution turns brown. This is due to which one of the following types of reactions?

Which one of the following statements regarding oxidation and reduction reactions is NOT correct ?

Copper sulphate crystals available in the market are blue coloured crystals. By careful heating, they turn to white colour. Which one of the following is responsible for the blue colour ?