Which one of the following metals is kept immersed in Kerosene oil to protect it and to prevent accidental fire ?

Sodium is a highly reactive alkali metal that reacts vigorously with both oxygen and moisture present in the air [1]. When exposed to water, the reaction is extremely violent and exothermic, generating enough heat to cause the evolved hydrogen gas to catch fire. To prevent such accidental fires and protect the metal from tarnishing or reacting, sodium must be stored in an inert environment. It is typically kept immersed in kerosene oil or mineral oil, which acts as a barrier against air and moisture [1]. While other metals like potassium share this property, among the given options, sodium is the standard example of a metal requiring storage under kerosene [1]. In contrast, calcium reacts less violently with water, and magnesium is generally stable enough to be handled in air.

Sources

1. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 4: The World of Metals and Non-metals > Activity 4.6: Let us investigate (demonstration activity) > p. 52