15. If a solution containing initially 25 mg/L trisodium NTA is allowed to come toequilibrium with solid PbCO3 at pH 8.50 in a medium that contains 1.76 ´ 10-3 MHCO3- at equilibrium, what is the value of the ratio of the concentration of NTA
bound with lead to the concentration of unbound NTA, [PbT-]/[HT2-]?