Consider a buffer with a pKa of 7. In a beaker of 100 mL of pure water, you dissolve HA and A- forms into the beaker until [HA] = [A-] = 5.5 mM. What volume of 1 M HCl do you have to add to change the pH of the solution to 6? Assume that the change in volume from adding HCl is negligible. Recall that pH = pKa + log([A-]/[HA]. I cannot, for the life of me, figure this out.