washing soda vs sal soda

washing soda and sal soda both are nouns.

Word	Noun	Adjective	Verb	Adverb
washing soda	Yes	No	No	No
sal soda	Yes	No	No	No

As nouns, washing soda and sal soda are synonyms defined as:

washing soda and sal soda: a sodium salt of carbonic acid; used in making soap powders and glass and paper

Other synonyms of washing soda include soda, soda ash, sodium carbonate.

washing soda (noun)	sal soda (noun)
a sodium salt of carbonic acid; used in making soap powders and glass and paper	a sodium salt of carbonic acid; used in making soap powders and glass and paper