capital of Liberia vs national capital

capital of Liberia and national capital both are nouns.

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

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