Chemical Forums

Specialty Chemistry Forums => Biochemistry and Chemical Biology Forum => Topic started by: prague441 on March 11, 2021, 05:41:14 AM

Title: Buffer Question
Post by: prague441 on March 11, 2021, 05:41:14 AM

The pKas citric acid are pK1 = 3.1, pK2 = 4.1, pK3 = 6.4. You were tasked to prepare 1L of a 0.5 M of citrate buffer at pH 4.0. The problem is, only solid trisodium citrate is present in the lab stockroom. How will you prepare the buffer then?

Title: Re: Buffer Question
Post by: chenbeier on March 11, 2021, 07:01:42 AM

In this case you cannot make a clean buffer. You have to add some other acid to convert the trisodiumsalt to Di or Monosodiumsalt so it fits to the Henderson  Hasselbalch  equation.
Probably HCl or H₂SO₄ can be used if chloride or sulfate will not disturb.