Why is baking powder a substance

Baking powder is a dry chemical leavening agent, a mixture of a carbonate or bicarbonate and a weak acid. Because carbon dioxide is released at a faster rate through the acid-base reaction than through fermentation.

Baking powder is a mixture because it contains both sodium hydrogen phosphate and potassium hydrogen tartrate (two different compounds.)

i think slash and

catya that's not even a b or c