impact vs touch on

impact is a noun but touch on is not a noun.

Word	Noun	Adjective	Verb	Adverb
impact	Yes	No	Yes	No
touch on	No	No	Yes	No

As verbs, impact and touch on are synonyms defined as:

Other synonyms of impact include affect, bear on, bear upon, touch.

impact (noun)	touch on (noun)
influencing strongly
the violent interaction of individuals or groups entering into combat
the striking of one body against another
a forceful consequence; a strong effect

impact (verb)	touch on (verb)
have an effect upon	restore by replacing a part or putting together what is torn or broken
press or wedge together; pack together	have an effect upon
	refer to or discuss briefly
	be relevant to