chlorination vs chemical action

chlorination and chemical action both are nouns.

Word	Noun	Adjective	Verb	Adverb
chlorination	Yes	No	No	No
chemical action	Yes	No	No	No

As nouns, chemical action is a hypernym of chlorination; that is, chemical action is a word with a broader meaning than chlorination:

chlorination: the addition or substitution of chlorine in organic compounds
chemical action: (chemistry) any process determined by the atomic and molecular composition and structure of the substances involved

Other hypernyms of chlorination include chemical change, chemical process.

chlorination (noun)	chemical action (noun)
disinfection of water by the addition of small amounts of chlorine or a chlorine compound	(chemistry) any process determined by the atomic and molecular composition and structure of the substances involved
the addition or substitution of chlorine in organic compounds