national capital vs capital of Mexico

national capital and capital of Mexico both are nouns.

Word	Noun	Adjective	Verb	Adverb
national capital	Yes	No	No	No
capital of Mexico	Yes	No	No	No

national capital (noun)	capital of Mexico (noun)
the capital city of a nation	the capital and largest city of Mexico is a political and cultural and commercial and industrial center; one of the world's largest cities