Sciencemadness Discussion Board

OTC Hydrofluoric Acid

rollercoaster158 - 17-5-2012 at 07:15

I have no idea what to make of this. It appears that Whink brand rust remover contains 3% hydrofluoric acid, something that is extremely difficult to obtain otherwise. You can buy a 16 floz bottle of it at Ace hardware for a few bucks. Is this one of those "too good to be true" moments, or are we looking at cheap over the counter hydrofluoric acid? If so, then we have some easy synthesis routes to NaF and even fluoroform. Here's a picture of the bottle, you can easily read "contains hydrofluoric acid" on the warning text.

http://mserv.toolking.com/catalog/product/W/h/Whink_Products...

[Edited on 5-17-2012 by rollercoaster158]

blogfast25 - 17-5-2012 at 09:45

3 % and a load of other junk. Not worth bothering with, IMHO.

Polverone - 17-5-2012 at 10:25

It contains a small amount of denatonium benzoate also to discourage ingestion. It could be purified by simple distillation. It is a convenient source of HF, albeit dilute and with a high price per mole.

Mailinmypocket - 17-5-2012 at 12:29

Depending on what you need HF for it might be easier and cheaper to use ammonium bifluoride as it forms Hydrofluoric acid in situ. Elemental scientific sells it at a reasonable cost!

AJKOER - 17-5-2012 at 13:59

In diamond district of New York City, you can buy a large plastic bottle of concentrated HF OTC if you are involved in the diamond business. What is scary is that the people who buy this stuff (to remove impurities from raw diamonds) just carry it down a busy street and may not even know its properties. What if they dropped a bottle and it ruptured? At least a chemist would know to hold his breath and run.

I agree with the in situ preparation route.

rollercoaster158 - 17-5-2012 at 14:06

Well, I thought that HF was expensive after I checked all the chemical suppliers. I was just interested. Maybe we can use a vacuum to siphon out all the HF gas, then redissolve it in much less water. It'll be purer and more concentrated. Keep in mind that I don't really need HF, I was just surprised that such a powerful and difficult to obtain acid would be in the grocery store.

S.C. Wack - 18-5-2012 at 14:09

No membership on the internet is more familiar with what's in things.
Stores also used to have methanearsenate, tryptophan, and sodium hydroxide.

Having no use for the acid, neutralization and evaporation gave perfectly good NaF, many years ago. Still have some.


[Edited on 18-5-2012 by S.C. Wack]