One of the buffers that contribute to ph stability in human blood is carbonic acid (h2co3). carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion (hco3-) and a hydrogen ion (h ), as noted below. if the ph of blood drops, one would expect one of the buffers that contribute to ph stability in human blood is carbonic acid (h2co3). carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion (hco3-) and a hydrogen ion (h ), as noted below. if the ph of blood drops, one would expect the hco3- to act as a base and remove excess h by the formation of h2co3 the concentration of bicarbonate ions (hco3-) to increase the hco3- to act as an acid and remove excess h by the formation of h2co3 a decrease in the concentration of h2co3 and an increase in the concentration of hco3-