# What makes Citrate or Citric Acid an acid?

As far as I know, an acid is something that gives off a proton or hydrogen ion $H^{+}$.

But when I look at Citric Acid,

There are three $COO^{-}$, which I think is a carboxyl group, that lacks $H^{+}$.

They seem to rather demand a hydrogen ion from its environment than donate one, which make it basic and not acidic. But the name is still citrate or citric acid. Can someone explain?

• That's not citric acid, that's the citrate anion. Replace those negative charges with hydrogen atons to get citric acid. The citrate anion is a base, and does demand protons from the environment. – user137 Sep 20 '18 at 5:38
• my mistake. It is from biology text book and citrate appears in Kreb cycle. That was why I posted this question here. And also somehow the text book says that is citric acid. And that is from Kreb cycle. – 강승태 Sep 21 '18 at 4:36