How does a buffer resist change in pH upon addition of a strong acid? The strong acid reacts with the weak base in the buffer to form a weak acid, which produces few H* ions in solution and therefore only a little change in pH. The strong acid reacts with the weak acid in the buffer to form a weak base, which produces few H* ions in solution and therefore only a little change in pH. The strong acid reacts with the strong base in the buffer to form a salt which, produces few H* ions in solution and therefore only a little change in pH.