Meixner test

[Fundisi]

Hi, I have a query regarding testing for amatoxins - is "spirits of salt" as sold in hardware stores concentrated enough hydrochloric acid to be able to perform a Meixner test? (the label says it is 25% HCL)

(Caveat: I am not silly enough to attempt eating any amanita look-a-like mushrooms that test negative - this test is for scientific curiosity only.)

[Jim Ford]

25% is pretty strong - you'll choke on the fumes. Hydrochloric Acid is a solution of Hydrogen Chloride in water, so you won't get 100%.

Purely a guess, but I would suspect 25% is too strong.

Jim

[Fundisi]

One does need to open the container far from one's nose, yes.

[Ditiola]

Hi

I typed in "How concentrated is 'Concentrated Acid' " into Google and found this, I hope it is of some use!


" First, it is important to describe a few aspects of concentrated mineral acids (as well as that of many other solutions). Most of us buy concentrated acids to use as stock solutions in the laboratory. None of these acids are one hundred percent pure. Sulfuric acid is only about 97% pure, nitric is about 69.5%, and hydrochloric acid is about 37.5% pure. Manufacturers of these acids simply cannot economically make these acids more concentrated than these respective percentages.

Another important aspect of these solutions is their specific gravities. The specific gravity of a liquid is, in most cases, synonymous with the more familiar term of density. Water has a specific gravity of 1. If the specific gravity of a liquid is greater than 1, then the liquid is heavier than water. Less than 1, and the liquid is lighter than water. The specific gravity for concentrated sulfuric acid is about 1.84, or 1.84 times heavier than an equal volume of water. The specific gravity of concentrated nitric acid is about 1.42 and that of concentrated hydrochloric acid is about 1.19.

Both the percent concentration and specific gravity values of the acid are required to determine the amount of concentrated acid needed when making a Normal solution. This information is usually printed on a label attached to the bottle of acid. Specific values vary depending on the manufacturer and lot of acid. "

[poschiavanus]

There's a reasonable description on wikipedia.

Industrial grade concentrated HCl is around 30% which is about 10 molar. In the bad old days before H&S was taken seriously I used to clean stills with it, but even then I made sure no-one else was in the room, had all the windows open and wore protective gloves and a lab coat. I'd be a little surprised if this is the concentration of the commercial 'spirits of salt' products: but I might nip down to the plumbers' merchant as it will clean out the drains nicely.

[Jim Ford]

Originally Posted by poschiavanus

In the bad old days before H&S was taken seriously I used to clean stills with it, but even then I made sure no-one else was in the room, had all the windows open and wore protective gloves and a lab coat. I'd be a little surprised if this is the concentration of the commercial 'spirits of salt' products: but I might nip down to the plumbers' merchant as it will clean out the drains nicely.

I think you'll need to take the same precautions with commercial 'spirits of salt'!

You can buy 500ml bottles in hardware shops, but if you're going to use it regularly it's cheaper to buy 5 litres from a plumbing suppliers. IIRC I paid around £12 for 5 litres about a year ago.

Jim