Could someone please tell me the strength of a phosphoric acid solution that would be equivalent (in acidity) to one liter of 5% vinegar? The neighbor's dog is about to do a BLAB tek and he doesn't have vinegar on hand, but does have plenty of phosphoric acid.

Just looking for the amount of phosphoric to add to a liter of water. In fact he doesn't even know the strength of his phosphoric yet, but is about to make calls and/or look up the MSDS to find this out; the source is "Advanced Nutrients" (gag) pH down, which is somewhat concentrated P-acid.

Thanks so much!

LB

Just found out that "Advanced Nutrients pH Down" is 85% phosphoric acid, in case it helps anyone else...

It is an easily obtained source of concentrated clean H3PO4.

Well, there's 0.873 mols of acetic acid in a liter of 5% vinegar, and the same number of mols in 50.799 ml. Of course there are three acidic protons on phosphoric acid (the pKas are 2.148, 7.198, and 12.375), so to a rough approximation, 25 ml of your 85% solution ought to be roughly equivalent.

Of course, if you're talking about the first step of the BLAB, the amount of acid really is not important. Add a dash of acid to a liter of water to acidify it and you're good to go. No need to get caught up on exact measurements.

Thanks Entropymancer. Call me a little anal, but I like to get a little more exact than "a dash" even though I totally believe you that it doesn't matter in this case. Maybe I'm a little obsessive. So I thank you for the math.

So 25 mL "pH down" into one liter of water it is, then... LB will tell Fluffy. Thanks again!