Here's why sodium metal is stored in oil:

* Reactivity with Air: Sodium is highly reactive with oxygen in the air. It quickly forms sodium oxide, a white powder, which can ignite and cause fires.

* Reactivity with Water: Sodium reacts violently with water, producing hydrogen gas (which is flammable) and a lot of heat, which can also cause fires and explosions.

Storing in Oil:

* Mineral oil is an inert substance that doesn't react with sodium metal. It creates a barrier between the sodium and the air and water, preventing any dangerous reactions.

Important Note: Even though it's stored in oil, sodium metal still needs to be handled with extreme caution. Always wear appropriate safety gear, such as gloves and goggles, when working with it.