A Study of the System Carbonic Acid, Carbon Dioxide and Water

ALTHOUGH the quantitative equilibrium relations in the bicarbonate-carbonic acid systems are very accurately known in biological solutions, it is a remark- able fact that only little is known about the way in which this equilibrium is attained and about the velocities of the reactions occurring. Still it might be supposed that this equilibriuim is not reached at once, as in purely ionic reactions, but that it is a very definite time-process under certain conditions. Thus the buffer-capacity of a bicarbonate system, after addition of a stronger acid, is calculated from the apparent dissociation-constant (k1 = 3 x 10-7), but it is possible that initially the system is reacting according to the true con- stant of carbonic acid (k1 = 4 x 10-4) during a biologically significant time, with a consequent large temporary increase of the resulting cH. If the carbonic acid were produced continuously, it might then be acting continuously as a strong acid.