Chemical Forums

Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: myelver10 on November 23, 2004, 02:29:07 AM

Title: preparing a buffer
Post by: myelver10 on November 23, 2004, 02:29:07 AM

how would u  pick a suitable acid/base pair  to prepare a buffer with a pH of 3.5    

In this case the pKa is 3.5  right   ??

Title: Re:preparing a buffer
Post by: AWK on November 23, 2004, 09:10:32 AM

For weak acid with pKa = 3.5 your buffer solution should contain salt and weak acid with molar ratio 1:1. Of course you can use other acids, but with pKa within +-1 around pH of solution.
Formic acid with pKa 3.7 is probably the best choose.