Al Qahira vs national capital

Al Qahira and national capital both are nouns.

Word	Noun	Adjective	Verb	Adverb
Al Qahira	Yes	No	No	No
national capital	Yes	No	No	No

Al Qahira (noun)	national capital (noun)
the capital of Egypt and the largest city in Africa; a major port just to the south of the Nile delta; formerly the home of the Pharaohs	the capital city of a nation