1 What is the fraction of A^- in a 1 M solution of A^- and HA that is at a pH of 5? pKa of HA=7.

2. Calculate the pH of a solution that is formed by mixing 25 mL of 0.1 M HCl with 10 mL of .2 M NaOH. First solve the following in the usual way.  Then solve it using the  charge balance equation.  (Hint : One of the four term can be neglected -explain which one).