A small amount of acid is added to a buffered solution. What will happen? The pH will change very little, if at all. The buffer will accept the hydrogen ions from the added acid, keeping pH constant. The pH will decrease rapidly after acid is added. The pH will increase rapidly after acid is added. The pH will change very little, if at all. The buffer will donate extra hydrogen ions to the solution to keep the pH constant.

Question

A small amount of acid is added to a buffered solution. What will happen?  The pH will change very little, if at all. The buffer will accept the hydrogen ions from the added acid, keeping pH constant.  The pH will decrease rapidly after acid is added.  The pH will increase rapidly after acid is added.  The pH will change very little, if at all. The buffer will donate extra hydrogen ions to the solution to keep the pH constant.

alistairgarratt · Answer

This depends on the pH of the solution prior to adding the acid....buffers only have a limited capacity either side of their useful range. Using the Henderson-Hasselbalch equation is also advisable.

anonymous · Answer

@nina20144 If the buffer does not end up past its capacity, the pH will change very little.  Frequently though tests and students are told it will not change the pH.  This is not true.

I am attaching pdf of notes I wrote up for my undergraduates' Intro Bio class.  The buffer is on the very first page, but more than just that is covered.