Potassium Is a Very Reactive Metal, but in Compounds It

Potassium is a very reactive metal, but in compounds it is present as the potassium ion and is not very reactive.For example, dry potassium bicarbonate powder can be used to extinguish burning liquids.Why is there such a difference in the reactivity of potassium metal and the potassium ion?

A) The potassium metal can readily ionize by losing its one valence electron; the potassium in the bicarbonate salt is already ionized.
B) The potassium atom is bonded to an oxygen atom in the bicarbonate salt, but in the metal it is unbound and free to react.
C) The combustion of the liquids suppresses the potassium's ability to react.
D) The potassium in the bicarbonate salt is a base, but the potassium metal is an acid.
E) The potassium in the bicarbonate salt is an acid, but the potassium metal is a base.