We had a Chemistry lab for buffer system, we used HCl and NAOH. We did a graph ( PH vs ml of HCL and NaOH, we told to estimate the buffer capacity using the graph. How to do this?

Answer 1

Buffer capacity can be defined in a variety of ways; the one I use is, "the mols of strong acid or strong base that can be added to 1 L of a buffer that will change the pH by 1 unit. You look at your graph and read the beginning pH and mols (say acid) then find the pH that is 1 unit higher and read mols HCl there. The difference in mols in the buffer capacity. Although we dn't normally think of strong acids or strong bases as buffers, they are buffers in reagions NOT near the equivalence point.

Answer 2

Thanks, you mean finding n for acid or base? The graph represent only PH and volume we added for acid or base in ml.