[fl0werb]

I need to make a buffer solution with a PH of 10.10. I can use HCL, NaOH, C6H5ONa (PKb=4.00), CH3COONa (Pkb=9.25), and CH3COOH (PKa=4.75).

None of the acids have a PKa close to the PH, I know the pOH is roughly 4 so C6H5ONa is an ideal base. Not sure where to go from there.

Edit: I should have specified that I have to use two species to add to water to prepare the buffer. Then I have to find the ratio of moles of the two species.

[Babcock_Hall]

I think that you may be confusing pOH with something else.

[Borek]

How are pKa and pKb related?

[fl0werb]

I'm not sure if I'm replying to the right reply, so I'll just reply to both.

My understanding of making a buffer is that it's ideal to use an acid that has a Pka close to the Ph, so I figured that it is also true that a base with a PKb close to the pOH is better.

Pka and Pkb sum to 14, so the Pka for the C6H5ONa is 10 (really close to PH so good!) but I don't know what other species to use with it.

[Babcock_Hall]

Are you familiar with the Henderson-Hasselbalch equation?

[fl0werb]

Yes.

So far what I've got to is

PH= Pka - log [acid/base]

Using the Pka from the conjugate acid of CH3COONa which would be 10, I then have .1= -log[acid/base]

I then found the ratio of acid to base to be .79

Now what I'm confused is to how much HCL I should add to the solution to produce that ratio of conjugate acid to base.

[Borek]

See if these help: https://www.chembuddy.com/?left=buffers&right=composition-calculation