## Chemistry: The Central Science (13th Edition)

${HCO_3}^-$ is a weak base. Conjugate acid: $H_2CO_3$, which is a weak acid.
${HCO_3}^-(aq) + H_2O(l) --> H_2CO_3(aq) + OH^-(aq)$ Since $H_2CO_3$ is the $H{CO_3}^-$ after receiving one proton, it is the conjugate acid. Since $H{CO_3}^-$ is a weak base (but not insignificant), his conjugate acid will be weak too.