interrogative vs interrogate

interrogative is a noun but interrogate is not a noun.

Word	Noun	Adjective	Verb	Adverb
interrogative	Yes	Yes	No	No
interrogate	No	No	Yes	No

interrogative (noun)	interrogate (noun)
a sentence of inquiry that asks for a reply
some linguists consider interrogative sentences to constitute a mood

interrogative (adjective)	interrogate (adjective)
relating to the use of or having the nature of an interrogation
relating to verbs in the so-called interrogative mood

interrogative (verb)	interrogate (verb)
	pose a series of questions to
	transmit (a signal) for setting off an appropriate response, as in telecommunication