potassium hydrogen carbonate vs potassium acid carbonate

potassium hydrogen carbonate and potassium acid carbonate both are nouns.

Word	Noun	Adjective	Verb	Adverb
potassium hydrogen carbonate	Yes	No	No	No
potassium acid carbonate	Yes	No	No	No

As nouns, potassium hydrogen carbonate and potassium acid carbonate are synonyms defined as:

potassium hydrogen carbonate and potassium acid carbonate: a crystalline salt (KHCO3) that is used in baking powder and as an antacid

Other synonyms of potassium hydrogen carbonate include potassium bicarbonate.

potassium hydrogen carbonate (noun)	potassium acid carbonate (noun)
a crystalline salt (KHCO3) that is used in baking powder and as an antacid	a crystalline salt (KHCO3) that is used in baking powder and as an antacid