* Reactivity: Sodium is a highly reactive metal. It reacts vigorously with water, oxygen, and even moisture in the air. This reaction produces heat and can even cause a fire or explosion.
* Protection from Air and Moisture: Mineral oil provides a protective barrier against air and moisture. It prevents sodium from reacting with these elements, keeping it safe and stable.
* Inertness: Mineral oil is chemically inert, meaning it doesn't readily react with sodium. This ensures that the sodium remains pure and uncontaminated.
* Density: Mineral oil is denser than sodium, so it can effectively cover and protect the metal.
Polythene, on the other hand, would not offer sufficient protection against sodium's reactivity. It's permeable to oxygen and moisture, and sodium would quickly react with these elements, causing potential hazards.
