national capital vs capital of Liberia

national capital and capital of Liberia both are nouns.

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

national capital (noun)	capital of Liberia (noun)
the capital city of a nation	the capital and chief port and largest city of Liberia