Carbonate Buffering in Acid Titration

The titration of sodium carbonate with hydrochloric acid shows how a polyprotic base reacts in stages. A polyprotic base can accept more than one proton, so its titration curve has two equivalence points. These points mark where one form has been fully changed into the next.

At the first equivale...

A polyprotic bronsted base like sodium carbonate reacts with water in two successive steps.

In its titration with hydrochloric acid, the initial pH estimated from the first dissociation constant of sodium carbonate is 11.6. The solution slowly turns acidic, demonstrating two equivalence points on the titration curve.

At the first e...