How do buffer solutions work and why can you not evaluate the pH of very pure water?
Buffer solutions work because there is a buffer that releases Hydrogen or Hydroxide, or accept one or the other or both. Basically this means that when you increase the number of Hydrogen ions present in a solution a buffer will start accepting hydrogen ions and also giving off hydroxide ions to keep the ph constant. Or if the solution becomes alkolotic it will start accepting OH ions and giving off hydrogen ions. This keeps the solution from changing ph very much. Lets say you have an ammount of water ph of 7. You have a buffer in the water. You then add enough acid to the water(enough acid to normally lower the ph to 3) but it only lowers the Ph to 6.8, still very close to 7. You then decide to take fresh water with buffer and add a base enough to raise the Ph in unbuffered water to 11. The Ph in the buffered water raises to 7.2. As you can see the ph does change when you add acid or base but it changes very little when you have a buffer. A classic example of a buffer system is your
