Washing Soda(Sodium Carbonate/NatriumCarbonat) purity question?

I have two questions regarding the washing soda(domal wasch soda) which I bought in Rossmann(drug store) chain in Germany.

- Its written Reine Soda(Pure Soda), may I know how pure it will be?

- Wonder whether it is anhydrous or any other form?

* Plan to use as second bath in DD-23.

I just fry up a pan of Arm and Hammer Baking soda. Works fine.

It has been my experience that manufactures will tell you their purity standard.

Hello,
the most sold quality is the anhydrous form,frequent mol. weight 106. The second quality is the monohydrate mol. weight 124. The decahydrate is too expensive to transport as you have 180 g water for 106 g soda. Maybe you find the CAS Reg.-No. on the package. It is 497-19-8 for the anhydrous, 5968-11-6 for the monohydrate, 24551-51-7 for unspecified hydrates and 6132-02-1 for the decahydrate. Instead of anhydrous soda take the 1,17-fold amount, of the decahydrate you would have to take the 2,7-fold amount. In the devided D-23 the second bath is only an alkaline bath I think. The quality of the "Drogeriemarkt" soda should be good enough. The most frequent impurity could be a very small amount of sodium chloride. You can dry it in the baking oven, if you weigh it before and after you can calculate on the base of the mol. weights whether it is monohydrate, anhydrous or unspecified.

the wash aid I buy is the decahydrate I assume water is cheap... and Im paying.

Gerald C Koch said:

It has been my experience that manufactures will tell you their purity standard.

Click to expand...

I have also found that a phone call is all that is needed. The first person to whom you speak will say "all of our products are 100% pure" but when you explain that you're using it for a particular purpose for which it is not marketed and ask to speak to someone technical you will get your answer. Some products are labeled with their purity which can be very low, such as pool shops' products.

As far as I know it is pure and Soda sicc. I phoned the company that sells it. I think it was Heitmann. After about three days I got a chemist on the line and he told me it is pure. He was wondering why I wanted to know and I told him for my darkroom. He was suprised that darkrooms still exist.
I use it whenever I need carbonate.
It works for me.

Thank you all.

Hello,
I just got the material safety data sheet for "Heitmann Reine Soda". It is anhydrous sodium carbonate, mostly abbreviated as "Soda sicc."