pass on vs request

pass on is not a noun while request is a noun.

Word	Noun	Adjective	Verb	Adverb
pass on	No	No	Yes	No
request	Yes	No	Yes	No

As verbs, request is a hyponym of pass on; that is, request is a word with a more specific, narrower meaning than pass on:

pass on (noun)	request (noun)
	the verbal act of requesting
	a formal message requesting something that is submitted to an authority

pass on (verb)	request (verb)
transmit information	express the need or desire for
cause to be distributed	ask (a person) to do something
move forward, also in the metaphorical sense	inquire for (information)
give to or transfer possession of
place into the hands or custody of
transmit (knowledge or skills)
refer to another person for decision or judgment