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Sodium Carbonate concentration

 

I am looking for a titration to verify a 5% concentration of sodium carbonate / washing soda [affil links]. If some one could point me in the right direction I would appreciate it greatly.

Thanks,

Allan Jones
- Vancouver, Washington

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The titration for Sodium Carbonate content is not as easy as it sounds. The best way to determine the Carbonate content is to use an autotitrator to an endpoint of 4.1 pH. The equation at this end point would be

%Na2CO3=Volume*Conc.*Constant/Sample Mass

Constant = Molecular Mass of Na2CO3/(10*the equivalence #)

A different way to determine this % is to use an auto titrator to determine the second equivalence point. This is due to the fact that the first equivalence point is the bicarbonate ion. The equation would be the same.

The trick is that the z number is 2 and we have to use the second equivalence point.

I hope that helps

Thomas Rohrer
Columbus, Ohio
 

I think he's trying to sell you an Autotitrator (Naughty Commercial Boy). If it's a simple solution without other alkalies or metals then a straightforward 1 or 2-stage wet analysis will give good results (5 mins). I suggest you check out any first year university chemistry book. Failing that I suggest you ask the supplier for the Technical Data Sheets.

John Tuohy
- Ireland
 

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5% sodium carbonate; anything less than 500 gallons, and it is easier and less expensive to make up a new solution than it is to titrate it!

  
Tom Pullizzi
Falls Township, Pennsylvania
 

I bow to Tom's superior knowledge. Never thought of that!

John Tuohy
- Ireland