Why is sodium kept immersed in kerosene oil?

Explanation

Sodium is highly reactive metal and combines readily with `O_(2)` present in air to form oxide, which in turns reacts with mositure to form hydroxide which further reacts with `CO_(2)` to form carbonate. Therefore, to prevent the above reaction, sodium metal is kept under kerosene oil.
`Na+underset(("Air))(O_(2))rarrNa_(2)O`
`Na_(2)O+underset(("Moisture"))(H_(2)O)rarr 2NaOH`
`2NaOH+underset("Air")(CO_(2))rarr Na_(2)CO_(3)+H_(2)O`