black and white vs monochrome

black and white and monochrome both are nouns.

Word	Noun	Adjective	Verb	Adverb
black and white	Yes	Yes	No	No
monochrome	Yes	Yes	No	No

As nouns, black and white and monochrome are synonyms defined as:

black and white (noun)	monochrome (noun)
a black-and-white photograph or slide	a black-and-white photograph or slide
communication by means of written symbols (either printed or handwritten)	painting done in a range of tones of a single color

black and white (adjective)	monochrome (adjective)
not having or not capable of producing colors	having or appearing to have only one color