1. The problem statement, all variables and given/known data This question is for a lab write up. We prepared a 0.1 M citrate buffer with pH 4.0, we then diluted our buffer with deionized water 20 fold and then 50 fold. The subsequent changes in pH are as follows, 20 fold pH = 4.10 50 fold pH = 4.14 This confuses me because I have always been told that any water added will NOT have any affect. Is it just a fluctuation of the pH meter or am I missing something? The lab write up asks us if there is a change and says to use the Henderson Hasselbalch equation to explain our answer, no calculations necessary. It then asks if the original buffer would have the same "buffering capacity" as the 20 fold diluted one. I feel like they would but now I am confused do to the change in pH after dilution. I am really bad with chemistry so any help would be much appreciated! 2. Relevant equations Henderson Hasselbalch Equation pH = pKa + log10 ( [A-] / [HA] ) 3. The attempt at a solution Pure water is neutral with a pH of 7. The buffering capacity SHOULD be the same in my opinion, but what about the change in pH?