How can I prepare a 0.1M NaOAc buffer at pH 5 using titration?

AI Thread Summary
To prepare a 0.1M NaOAc buffer at pH 5, the initial approach of creating a 0.2M acetic acid solution and titrating with sodium hydroxide is flawed due to miscalculating the pH of acetic acid, which is actually around 2.88 for a 0.1M solution. To achieve the desired pH without altering the molarity, titration can be employed, provided that the pH meter is properly calibrated and the amounts of solutions used are accurately recorded. This method will help determine the necessary concentration of sodium acetate needed to reach pH 5. Resources like Chembuddy can provide additional guidance on buffer preparation.
ReidMerrill
Messages
65
Reaction score
2
For a lab I need to create a 0.1M solution of NaOAc buffer at pH 5
It's been a while since I worked with buffers. I'm struggling to find a way to get both the proper morality and proper pH.
My first though was to create a 0.2M solution of acetic acid and titrate it to pH 5 using sodium hydroxide. The problem is when I tried to calculate the pH of 0.2M solution of acetic acid I got a pH higher than 5 so I couldn't use sodium hydroxide to adjust the pH. I think this was a calculation error on my part though.

Any help would be greatly appreciated.
 
Chemistry news on Phys.org
Borek said:
Check this out: http://www.chembuddy.com/?left=buffers&right=toc

Yes, your calculation of pH is faulty, as pH of 0.2 M acetic acid is below 3.
I did some Google snooping and apparently the pH of a 0.1M solution of acetic acid is 2.88.

In that case, how do I raise the pH without lowering the molarity?
 
There are worked out examples at the link provided, why don't you check them?
 
ReidMerrill said:
For a lab I need to create a 0.1M solution of NaOAc buffer at pH 5
It's been a while since I worked with buffers. I'm struggling to find a way to get both the proper morality and proper pH.
My first though was to create a 0.2M solution of acetic acid and titrate it to pH 5 using sodium hydroxide. The problem is when I tried to calculate the pH of 0.2M solution of acetic acid I got a pH higher than 5 so I couldn't use sodium hydroxide to adjust the pH. I think this was a calculation error on my part though.

Any help would be greatly appreciated.
You COULD actually do the titration to determine, ultimately how to prepare your pH 5 buffer, as long as you carefully record how much of what concentrations of the solutions you used, as as long as you properly calibrated your pH meter before doing the titration. You should be able to figure how much sodium acetate is present once you reached pH 5. (This should be a beginner's lab exercise.)
 
I want to test a humidity sensor with one or more saturated salt solutions. The table salt that I have on hand contains one of two anticaking agents, calcium silicate or sodium aluminosilicate. Will the presence of either of these additives (or iodine for that matter) significantly affect the equilibrium humidity? I searched and all the how-to-do-it guides did not address this question. One research paper I found reported that at 1.5% w/w calcium silicate increased the deliquescent point by...
Back
Top