common salt vs chlorine

common salt and chlorine both are nouns.

Word	Noun	Adjective	Verb	Adverb
common salt	Yes	No	No	No
chlorine	Yes	No	No	No

common salt (noun)	chlorine (noun)
white crystalline form of especially sodium chloride used to season and preserve food	a common nonmetallic element belonging to the halogens; best known as a heavy yellow irritating toxic gas; used to purify water and as a bleaching agent and disinfectant; occurs naturally only as a salt (as in sea water)
a white crystalline solid consisting mainly of sodium chloride (NaCl)