To measure the amount of calcium carbonate in a seashell, an analytical chemist crushes a 4.80g sample of the shell to a fine powder and titrates it to the endpoint with 515ml of 0.140M hydrogen chloride solution. The balanced chemical equation for the reaction is: 2HCL(aq) + CO32-(aq) → H2CO3(aq) + 2Cl-(aq)

Required:
a. What kind of reaction is this?
b. If you said this was a precipitation reaction, write the chemical formula of the precipitate.
c. If you said this was an acid-base reaction, write the chemical formula of the reactant that is acting as the base.