Asked by Tom

what is the pH range of the buffering region?

is that when ph=pKa?

Answers

Answered by DrBob222
The best buffering is when pH = pKa. The RANGE, however, generally is considered to be +/- 1 from pKa. That's the definition of buffering capacity.
Answered by Tom
so if the pka is 4.5 the range will be from 3.5 to 5.5?
Answered by DrBob222
You can read more about it here.
http://www.cartage.org.lb/en/themes/Sciences/Chemistry/Inorganicchemistry/AcidsBases/Acidsbasesindex/Bufferrange/Bufferrange.htm
I think the buffer capacity is associated with the buffer range. The buffer capacity is defined as the amount of acid or base that can be added without exceeding +/- 1 in pH. The buffer range is the pH range that can be experience by the solution and still act as a buffer. And that is generally +/- 1 pH unit. Yes, in your case, that would be 3.5 to 5.5. A buffer with pKa 4.5 would be expected to work very well withing that range and would not be expected to work well outside that range.

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