Question

explain how the buffer H2CO3 neutralizes an acid that is added to a solution that contains it. if the pH of the solution was 5.0 before the acid was added, what would it be after the acid was added

Answer 1

You can add H2CO3 with NaOH to give NaHCO3 + H2O.
\[H_2CO_3 + NaOH \rightarrow NaHCO_3 + H_2O\]
NaHCO3 is basic, so, reacting with acid will neutralize and gives you the original product
\[HCl + NaHCO_3 \rightarrow H_2CO_3 + NaCl\]