ammonium alum vs Al

ammonium alum and Al both are nouns.

Word	Noun	Adjective	Verb	Adverb
ammonium alum	Yes	No	No	No
Al	Yes	No	No	No

As nouns, Al is a hypernym of ammonium alum; that is, Al is a word with a broader meaning than ammonium alum:

ammonium alum: a white crystalline double sulfate of aluminum: the ammonium double sulfate of aluminum
Al: a silvery ductile metallic element found primarily in bauxite

Other hypernyms of ammonium alum include aluminium, aluminum, atomic number 13, double salt.

ammonium alum (noun)	Al (noun)
a white crystalline double sulfate of aluminum: the ammonium double sulfate of aluminum	a silvery ductile metallic element found primarily in bauxite