Write two chemical equations, one in which $\mathrm{H}_{2} \mathrm{PO}_{4}^{-}$ is a Brensted acid (in reaction with the carbonate ion, $\left.\mathrm{CO}_{3}^{2-}\right),$ and a second in which $\mathrm{HPO}_{4}^{2-}$ is a Bronsted base (in reaction with acetic acid, $\mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{H}$ ).