Question

Why is sodium stored under kerosene and not under water?

Answer 1

Hint: We know that the sodium belongs to the alkali group. The atomic number of sodium is eleven. Sodium appears as white in colour, soft and is highly reactive metal. We have to know that sodium is the sixth most available element in the crust of the Earth. It occurs in the form of feldspars, rock salt, and sodalite. We know that the salts of sodium are highly water soluble.

Complete answer:
We know that sodium is highly reactive metal. It reacts with oxygen present in the air to produce sodium oxide at room temperature. So, it catches fire and begins to burn when it is present in the open air. It also reacts with water to form hydrogen gas that rapidly catches fire. In the presence of ordinary air, sodium reacts with water to produce a film of sodium hydroxide that fastly absorbs carbon dioxide and produces sodium bicarbonate. The density of sodium is higher than that of kerosene and it does not react with kerosene. Hence, we can store sodium in kerosene but not in water.
Therefore, the correct option is option (C).

Note:
We have to keep sodium under kerosene to avoid the reaction of sodium with oxygen, carbon dioxide, and moisture. When sodium reacts with water and oxygen a huge amount of heat is generated during this reaction. We have to know that sodium plays an important role in humans. It is an important mineral which controls the volume of blood, pressure of the blood, equilibrium and pH. In diet, the principal source of sodium is sodium chloride.