posted by Aria on .
Select the statements that correctly describe buffers.?
1) The pH of a buffer solution does not change significantly when any amount of a strong acid is added.
2) The Ka of a buffer does not change when any amount of an acid is added to the buffer solution.
3) The pH of a buffer solution is determined by the ratio of the concentration of conjugate base to the concentration of strong acid.
4) A buffer is generally made up of a weak acid and its conjugate base.
5) An acid added to the buffer solution reacts with the weak base of the buffer.
I think it is 2 and 4. I'm not really sure about the rest...
You're right. 2 and 4 are true.
1 is not true.
3. I don't know. It IS determined by the ratio of the base/acid BUT the pKa must be in there somewhere, also. Since pKa is not mentioned I would go with 3 being false.
5 I think is not a good part of the problem. An acid added to a basic buffer (e.g., NH4^+/NH3) does react with the weak base; an acid added to an acidic buffer (acetic acid/acetate) has no weak base in it. So it can be either right or wrong depending upon the kind of buffer in the problem.
Thank you very much!
2,4, and 5 are correct