4) The following questions will help you review and understand pH,pK, and buffering by weak acids/bases. a) Water is a weak acid; write the ionization reaction of water and the expression that describes its Ka. (Hint: Ka is the equilibrium constant for proton dissociation). b) What is the concentration of H+in a solution of water when the concentration of OH=108M ? What is the pOH of this solution? What is the pH ? Is the solution acidic or basic? c) Draw a titration curve for a molecule with a pKa=4.7 and label all the axis, indicating clearly the buffering region and the pKa value (like in Fig 2-17, Page 62)