[FouRRaW]

Hi, I got a pH buffer solution question i'm a bit confused on....

Acetic acid has a Ka=1.8x10^-5. What is the pH of a buffer solution containing 0.15M CH₃COOH and 2% CH₃COO^-?

So mainly i'm not really sure what the 2% means, and what i'm supposed to do with it?

Any tips or advice would be greatly appreciated.

Thanks
-fourraw

[AWK]

assume 2% w/w and density of solution that of water. Usually percent concentration is used for a specific compound. You need a molecular mass for  a molar concentration calculation

[Borek]

You may do as AWK told you, but the question is ambiguous. It may mean 0.15M acetic/acetate total, 2% of acetate, remaining form - acetic acid. In such a case just plug percentages into Henderson-Hasselbalch equation.

What I don't like about this question is that %w/w conversion to molarity will depend on the counterion. 2% w/w CH₃COONa solution has different moler concentration than CH₃COOCs, and I have never seen w/w concentration given just for ion (CH₃COO^- in this case).