Chemistry Help

[ASUSEAN1]

1.You are asked to prepare a buffer of pH 6.40 for a biological assay. Using the table of pKa's in the experimental procedure, select an appropriate acid/base pair and calculate how much of each you need to make 150 mL of buffer solution. Assume all solutions are 1 M.

The correct Acid/Conjugate Base pair is:
Acid: H_{2}PO_{4}^- or this if it's easier to read (H2PO4^-)
Base: HPO_{4}^2- or this if it's easier to read (HPO4^2-)

pKa=7.21

I think I understand how to make the acid/base ratio but not sure

So far I took the pH-pKa (6.4-7.21)=-.81
Then I took 10^-.81= .15

So would it be 1M acid to .15M of Conj. Base?
If so then how would you get the amount of mL of each?



2. Using the buffer solution prepared in question 1, what would be the resulting pH after the addition of 6.0 mL of HCL (1M)


Not just looking for answers.. explanation would be greatly appreciated

Thanks in Advance Edited October 14, 2009 by ASUSEAN1

[ASUSEAN1]

ps where is Eric when you need him?

[ASUSEAN1]

ps where is Eric when you need him?