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I wish to know how to test free acidity of the bath

Hello I'm working in a paint shop in Delhi. I know how to test and maintain total acidity of the bath but I'm unaware that how should I check the free acidity of my bath as I'm using chemicals of German based company?

Varun Kumar
paint shop employee - Delhi
June 21, 2008

July 11, 2008

Hi,

Can we please get more details on your question?

thanks

Terry Tomt
- Auburn, Washington

What kind of acids are you using? It's hard to tell which method to use without knowing what you're looking for (different acids have different titration methods).

Jason Rothman
Chemist - Pomona, California, USA
August 6, 2008

August 10, 2008

Sir,
The answer to your question is quite simple. As titrant you use a strong base (alkali). For total acidity (all the acid that you have added, use an indicator near neutral (e.g. phenolphthalein ⇦ this on eBay & Amazon [affil links] ). For "free" acid use an indicator that changes color perhaps between about 3 or 5.
Regards,

Dr. Thomas H. Cook
Galvanizing Consultant - Hot Springs, South Dakota, USA

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