Phosphoric acid

[Bloodman14]

Any chemists in the house? I have a large storage container full of phosphoric acid that I am using to de-rust and de-chrome some car parts for a resto-mod project. So far, everything is going well. At what point will the acid lose its' potency, and how would I tell?
Thanks.

[deltaenterprizes]

Litmus paper.

[Bloodman14]

I am guessing that it will show as being neutral? 7. something?

[BJK]

Yeah, pH. I'm guessing you'll figure it out when it stops working in your application. It'll also stop tasting like Pepsi or Coca Cola. (no don't do that!)

[jorg0370]

Mix a little sample with a little baking soda. If it does not bubble and off-gas, it has lost it's effectiveness.

[Bloodman14]

Gentlemen, I thank you for the info.