The pH of 0.005 M codeine CC18 H21 NO3 sol. Is 9.95 . Calculate it\'s ionization enthalpy and Pkb

The pH of 0.005 M codeine CC18 H21 NO3 sol. Is 9.95 . Calculate it\'s

1.	The pH of 0.005 M codeine CC18 H21 NO3 sol. Is 9.95 . Calculate it\'s ionization enthalpy and Pkb
Answer» From the pH we can calculate the hydrogen ion concentration. Knowing hydrogen ion concentration and the ionic product of water we can calculate the concentration of hydroxyl ions. Thus we have:\xa0[H+] = antilog (-pH)= antilog [-9.95]= 1.12 X 10-10So, [OH-] = Kw / [H+]= (1 X 10-14) / (8.91 X 10-5)= 8.91 X 10-5 MThe concentration of the corresponding codenium ion is also the same as that of hydroxyl ion. Let the codeine ion be denoted by [M+]. ThusKb = [M+][OH-] / [MOH]= (8.91 X 10-5)2 / 0.005= 1.59 X 10-6pKb = -log Kb = - log(1.59 X 10-6)pKb = 5.80