Question

These metal(Lithium, sodium, potassium) reacts vigorously with atmosphere and get corroded. To prevent this corrosion,
sodium and potassium are immersed in kerosene. But for lithium a wax coating is given but is not immersed in kerosene like
other two. Why?​

Answer 1

Explanation:

Sodium, Lithium, potassium reacts with oxygen, so it has to be kept away from air. Storing it under a liquid is an easy way to do that. Water is our usual go-to liquid, but sodium reacts with water (and also floats on top, because it’s less dense than water), so water is not a good choice. Sodium also reacts with alcohols, so those are no good. It does not react with hydrocarbons, and is denser than all the ones I can think of, so they are a good choice. Kerosene is cheap, pretty non-toxic, does not evaporate as fast as some hydrocarbons, and so is a pretty good choice.

However, for long-term storage, mineral oil is preferred, since kerosene will evaporate eventually if the container is not perfectly sealed.