capital of Argentina vs Buenos Aires

capital of Argentina and Buenos Aires both are nouns.

Word	Noun	Adjective	Verb	Adverb
capital of Argentina	Yes	No	No	No
Buenos Aires	Yes	No	No	No

As nouns, capital of Argentina and Buenos Aires are synonyms defined as:

capital of Argentina and Buenos Aires: capital and largest city of Argentina; located in eastern Argentina near Uruguay; Argentina's chief port and industrial and cultural center

capital of Argentina (noun)	Buenos Aires (noun)
capital and largest city of Argentina; located in eastern Argentina near Uruguay; Argentina's chief port and industrial and cultural center	capital and largest city of Argentina; located in eastern Argentina near Uruguay; Argentina's chief port and industrial and cultural center