Why is the stability of a compound considered a chemical property?

Chemical property is the ability of a substance to react with other substances or to transform into other substances. The stability of a compound indicates how much it "prefers" to remain as such or to get transformed. Then the stability is a chemical property.

Here is the explanation of the given question above. When we say chemical stability, it refers whether the chemical will react with air or water because a substance that is stable will not react. When the compound is unstable, this results in the breakdown and formation of a new substance which results in a chemical change.