another question about chemical buffers.?

Question

I put a drop of NaOH into a beaker that had a buffer with a pH of 7 in it, and the pH rose by 0.01 and then i put 3 moe drops of NaOH and the pH rose by 0.01. How does the buffer control the pH.

Then I put a drop of HCl into another beaker with a buffer with a pH of 7 in it, and the pH rose by 0.05 and then i put 3 more drops of HCl into the same beaker and the pH lowered by 0.03. Then I put 6 more drops of HCl into the same beaker and the pH lowered by 0.01. why did the pH rise then lower, and how does the buffer control it.

Answer 1

The buffer has unionised molecules which undergo ionisation to maintain the pH when H+ or OH- ions are consumed or added.

Answer 2

buffer solutions are those with both acids and bases in a balance in them already.
Like Acetic acid and sodium acetate(conjugate base) solutions. The buffer at pH 7 means that the ratio between acids and bases is 1:1 with the giiven concentrations. Buffers work because the two chemicals are in equilibrium at those levels.
if you add some acid, the base reacts with it and destroys it, but since the acetic acid and sodium acetate like to maintain a specific ratio of 1:1 between the two, some of the acetic acid then transforms to acetate to make up for the spend acetate. thus restoring the ratio of 1:1 for acid:base
The exact pH balance point varies slightly as some of the components are expended.