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Q&As since 1989
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Nitric Strike Tank Test Question
Q. I work for a metal finishing shop and have a little problem. Our pH meter has had a heart attack. I am now in a process of turning my tank titration testing procedures from using the pH meter to using indicators. I have done a pretty good job until I ran into the testing of our Nitric Strike tank; tank containing ~45-50% nitric acid concentration. I have tried consulting our books and have not been able to find a titration method that utilizes an indicating solution that has the appropriate visual transition. Should I use Thymol Blue, an indicator with visual transition of 1.2 - 2.8 from red to yellow? If you have any ideas, I am more than willing to listen to them.
Thanks,
Noel Yangplating shop - Oldsmar, Florida, USA
2004
A. That will work, but one that changed color around a pH of 4 would be a more normal choice. Experiment with methyl orange [on eBay or Amazon] and with methyl red <-- searched 4/14/24 --> [on eBay & Amazon] . Cheap and functional. I preferred 0.5 N sodium hydroxide [on eBay or Amazon] over 1.0N because it is weaker and does not tend to precipitate out any metals because of a locally high pH. A mixer with a teflon spin bar works a lot easier than swirling with an erlenmeyer Flask. It is worth the extra few bucks in the long run.
James Watts- Navarre, Florida
2004
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