identifying acids

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mtg
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identifying acids

Post by mtg » 23 Jul 2019, 11:34

I have "pickle", an acid powder from the metalwork room. How do I identify it? I would think it was HCl but curiosity has me wanting to prove it.

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Labbie
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Re: identifying acids

Post by Labbie » 23 Jul 2019, 12:53

Pickling is a metal surface treatment used to remove impurities, such as stains, inorganic contaminants, rust or scale from ferrous metals, copper, precious metals and aluminum alloys. A solution called pickle liquor, which usually contains acid, is used to remove the surface impurities. Wikipedia
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bigmack
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Re: identifying acids

Post by bigmack » 23 Jul 2019, 14:01

I know that some Pickle used for stainless steel contains Hydroflouric Acid which is a DET banned chemical .....but its a liquid .

You gave a powder that is added to water to make a pickle solution .

A quick google showed Citric acid and sodium bisulpfate being common .One is food grade , the other is toxic .

Bottom line though to me is if its not labelled , then you have no access to an SDS and it should not be stored or used .
mtg wrote:
23 Jul 2019, 11:34
How do I identify it? I would think it was HCl but curiosity has me wanting to prove it.
You could drop some silver nitrate into a sample . The Chlorine will cause a white precipitate .
Acid test.jpg
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mtg
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Joined: 15 Aug 2011, 10:48
Job Title: Lab Tech
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Re: identifying acids

Post by mtg » 24 Jul 2019, 13:19

YAY, The "Pickle" is HCl. (AgNO3 test) We used to make up a % to dip metal before enamelling as I recall. Probably same as the powder you get to chlorinate pools. It amazes me how the Art and Metal/Wood work have these sort of labels.

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