The Student Room Group

Buffers

Screenshot 2022-04-14 at 14.46.58.pngFrom my knowledge the only requirement for a buffer solution is a weak acid and it's salt, however when attempting this question it talks about monoprotic acid when lead me to think that the moles of the salt and acid would have to be the same to have the same molar ratio but not sure about it either. Could someone hint me with what I'm missing?
(edited 1 year ago)
@Student 999 Because it is monoprotic, it would react in a 1:1 ratio with the NaOH.
How do buffers work? You need the acid to be present in the solution alongside the conjugate base.
If we chose the first one, you would have an excess of NaOH, no acid remaining, and so it wouldn't be a buffer.
What would happen if we chose the second? And if we chose the third?
(edited 1 year ago)
If you look at the pH curve for the titration of a weak acid and strong base, where does the buffer region occur? How much of the strong base has been added relative to the weak acid?
Original post by booklover1313
@Student 999 Because it is monoprotic, it would react in a 1:1 ratio with the NaOH.
How do buffers work? You need the acid to be present in the solution alongside the conjugate base.
If we chose the first one, you would have an excess of NaOH, no acid remaining, and so it wouldn't be a buffer.
What would happen if we chose the second? And if we chose the third?

Thanks I see what you mean, also another question is when referring to the half-equivalence point is it when half of the moles in the weak acid has been reacted? And what significance those that bring?
Original post by Student 999
Thanks I see what you mean, also another question is when referring to the half-equivalence point is it when half of the moles in the weak acid has been reacted? And what significance those that bring?

Yes, exactly. At the half-equivalence point, the pH=pKa, which is why it is significant.

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