Is a coin an alkali

Answer 1

No, a coin is not an alkali. It's a metal or metal alloy. Alkali metals are very reactive and coins are not made of them. These metals react with the water in air, so they are stored beneath a liquid they do not react with (like kerosene), or in a gas they will not react with (like an inert gas). Making coins out of alkali metals would give entirely new meanings to "depreciation" and the phrase "money burns a hole in my pocket."