I need helping explaining ny observations based on Le Chartlier's principle in part C & D. I also need help aswering the last wuestion on Part D

C. Barium Oxalate and Oxalic Acid Equilibria TU I I I there is not a clear distinction between test tube #2 and test tube #3 at the end of this section, add more acid to test tube #2 and more base to test tube #3. T ne same amount of HCl in moles could be added by adding 50mL of L2M. Why isn't this done? (Hint: consider the effect of adding 50mL of waterl)