iodination vs chemical action

iodination and chemical action both are nouns.

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

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

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

Other hypernyms of iodination include chemical change, chemical process.

iodination (noun)	chemical action (noun)
the substitution or addition of iodine atoms in organic compounds	(chemistry) any process determined by the atomic and molecular composition and structure of the substances involved