the PH of blood stream is maintained by a proper balance of H2CO3 and NaHCO3 concentrations. What volume of 5 M NaHCO3 solution , should be mixed with 10 ml sample of blood which is 2M in H2CO3 in order to maintain a PH of 7.4 . ka for H2CO3 in blood is 7.8*10^-7?