# Difference between 70 ° and 42 ° Nitric Acid



## roggiou (Feb 8, 2017)

Hello to all ! 
.... And sorry for my bad english .
I found nitric acid at 42 ° but, in addition to having a good price I would like to know if there will be diversity of reactions and if I have to follow normal proportions (1: 1 Nitric - Water in first step + 1: 3 Nitric: HCL for AR).
many thanks in advance for your answers and for the attention.


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## nickvc (Feb 9, 2017)

Welcome to the forum.
In honesty a weaker nitric is better to use than a strong one, the dilution makes more use of the active acid available which is why we dilute it normally and avoids forming crystals after dissolving metals, if you want to follow the advised dilution I'd go for 3 parts acid to 1 of water, if the price is much cheaper buy the 42 go for that.
Hope this helps.


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## aga (Feb 9, 2017)

Either acid concentration will work, and you will dilute it anyway, as nickvc said.

The 70° has more acid in the same volume, so if it is only a little bit more money than the 42°, it might be cheaper to get the 70°. As there is more acid in the bottle, it would also take up less space if that is an issue.


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## goldsilverpro (Feb 9, 2017)

I would guess that it is 42 degree Baume', which is the same as standard technical grade nitric acid of about 67%. Baume' is an old scale used for nitric and other things. It is measured with special Baume' hydrometers, is expressed with a degree symbol, and is often abbreviated as Be'. It is pronounced baw-may. 70% nitric is essentially the same (a little stronger) as 42 Be' nitric. For refining, they are interchangeable.

https://encrypted.google.com/search?q=42+baume+nitric&ie=utf-8&oe=utf-8&aq=t

https://en.wikipedia.org/wiki/Baum%C3%A9_scale


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## Lino1406 (Feb 9, 2017)

Exactly. The Baume degree refer to density and there is maybe a possibility of having 70 Baume, with 100% nitric (There is such a thing but I don't think it was offered in this case)


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## butcher (Feb 10, 2017)

http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?t=11772


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## aga (Feb 10, 2017)

goldsilverpro said:


> I would guess that it is 42 degree Baume' ... expressed with a degree symbol ...


A confusing 1874 paper i got about a year ago (make oxalic acid from lye & sawdust) uses the degree symbol a lot, and now the whole thing makes sense.

Thanks for that Superb info goldsilverpro !


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## g_axelsson (Feb 10, 2017)

I went ahead and made a translation table between Baumé and % for nitric and hydrochloric acid.

http://goldrefiningwiki.com/mediawiki/index.php/Baum%C3%A9

Göran


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## goldsilverpro (Feb 10, 2017)

Nice, Goran.

This whole Baume' idiocy was originally developed for salt solutions in some industry. For salt water it made sense. They should have kept it there. 

From Wikipedia:

_"Baumé degrees (heavy) originally represented the percent by mass of sodium chloride in water at 60 °F (16 °C). Baumé degrees (light) was calibrated with 0°Bé (light) being the density of 10% NaCl in water by mass and 10°Bé (light) set to the density of water."_


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## roggiou (Feb 16, 2017)

many thanks to all for the answers.


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## 4metals (Feb 17, 2017)

> This whole Baume' idiocy was originally developed for salt solutions in some industry. For salt water it made sense. They should have kept it there.



I didn't know this, when I was an undergrad taking chemical oceanography courses all salinity measurements were made in the field with hydrometers and they were calibrated in º Baume and specific gravity.

It was at a time when all of the old data was reported as Baume and the newer date was coming around to specific gravity. So we had to report in both scales. 

Interesting though, actual salinity in the lab was calculated with a silver nitrate titration.


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