Question

why is sodium and potassium kept in kerosene oil?

Answer 1

sodium and potassium r reactive elements if kept in open air or water they react to form other products
as kerosene is an organic inert solution they r suspended in it to get them in their original form always

Answer 2

Sodium and potassium is a very reactive metal. It iskept in kerosene to prevent it from coming in contact with oxygen and moisture. If this happens, it will react with the moisture present in air and form sodium hydroxide. This is a strongly exothermic reaction, and lot of heat is generated.