<prompt> In plasma, if pH is 5 , what is the fraction of base to acid?0.010.1110  <response>: Ans: b 0.1Ref: Vasudevan 4th edp.347According to Henderson-Hasselbach equation,pH pKa log pKa pH at which the acid is half ionised. It is a constantThe most important buffer system in plasma is bicarbonate- carbonic acid system. pKa for carbonic acid is 6.1 .pH pKa log rbasel5 6.1 log log rbasel -1.1 log 10-1 approx. 