Making Nitric Acid, oopsie

[Striker578]

I could use some help in understanding these 2 formulas for HNO2. I've seen Data using the stoichiometric found here> KNO3 + H2SO4 = HNO3 + KHSO4 - Reaction Stoichiometry Calculator

I also have the ratios here but never witnessed the result yet from "Webqc.org'.. There's a big difference between the two.
Example 299g of KNO3 from "Webqc.org" says 145.03g of H2SO4 But "Chemicalaid.com" says 290.0547g of H2SO4..
Can both be correct? Seem like one may result in an excess of acid or nitrate.
Can anyone clarify them methods?

 

[Yggdrasil]

I could use some help in understanding these 2 formulas for HNO2. I've seen Data using the stoichiometric found here> KNO3 + H2SO4 = HNO3 + KHSO4 - Reaction Stoichiometry Calculator

I also have the ratios here but never witnessed the result yet from "Webqc.org'.. There's a big difference between the two.
Example 299g of KNO3 from "Webqc.org" says 145.03g of H2SO4 But "Chemicalaid.com" says 290.0547g of H2SO4..
Can both be correct? Seem like one may result in an excess of acid or nitrate.
Can anyone clarify them methods?

This is a 1-1 molar formula where one mol KNO₃ + one mol H₂SO₄ reacts to one mol HNO₃ + one mol KHSO₄
When we put in the molar weights we get:
1 mol KNO₃ is 101,1032 g/mol
1 mol H₂SO₄ is 98,079 g/mol
1 mol HNO₃ is 63,01 g/mol
1 mol KHSO₄ is 136,169 g/mol
This is highly ideal and with pure chemicals, real life is different, but this recipe is for 3 mols of Nitric, appr 189 grams.

So depending on the amounts you want to make you need to increase or decrease the amount of reactants.

But seriously man, put everything aside and start studying, before you do anything, this is a very simple reaction...

 

[Striker578]

Thanks for the explanation. I comprehend the difference of the two sites data and Mole structure better. Theory & real practice are different. 100% H2SO4 & many acids is impractical, almost unachievable & rarely used. This must be taken in account. Part of my study is to ask when confused.

 

[James Ball]

I am assuming that the reaction will not go to 100% products leaving H2SO4 and KNO3 in solution to some extent. If I use HNO3 to dissolve sterling silver I could also make Ag2SO4. So, it seems to me that I should use KNO3 in excess to make sure all of the H2SO4 has reacted.

 

[Martijn]

I am assuming that the reaction will not go to 100% products leaving H2SO4 and KNO3 in solution to some extent. If I use HNO3 to dissolve sterling silver I could also make Ag2SO4. So, it seems to me that I should use KNO3 in excess to make sure all of the H2SO4 has reacted.

If you were making poor mans nitric, leaving excess KNO3 in would make sense to avoid having sulfuric in solution, but if you are distilling the nitric out not. Then you need excess H2SO4.

 

[Alondro]

I can't stress this enough......Hot 92% sulfuric acid is no joke..... it will scare you for life if any gets on your skin, even the vapors can damage your lungs. Just make sure you have protection.

Fuming nitric is just as bad, if not worse. The nitrogen oxides are toxic and potentially carcinogenic. They also don't play well with many other chemicals.

Basically, if you have ANY concentrated acids, protective clothing and ventilation is ESSENTIAL. HCl is the LEAST nasty to biology, since we're somewhat adapted to deal with it (every stomach produced it for digestion), but it will still dissolve your skin when in concentrated form and breathing in the vapors will form acid in the mucous membranes and lungs.

There is no 'safe' concentrated mineral acid.

 

[Wonka]

Don’t forget to add 20-30% water to your mix. Nitric won’t boil off if it is over 70% concentration. Unless you add some other acids to make fuming nitric. Which with any refining of precious metals you do not need.

 

[Yggdrasil]

Don’t forget to add 20-30% water to your mix. Nitric won’t boil off if it is over 70% concentration. Unless you add some other acids to make fuming nitric. Which with any refining of precious metals you do not need.

You need to reread your advice.
It do not make sense.

You do not get fuming Nitric by adding to it.
And boiling it will just reduce it down to azeotrope 68%.

 

[billgold]

If I recall correctly, the boiling point of nitric acid is about 83 degrees C. At that temperature, the nitric acid starts to decompose to water and nitric oxides, which reduces the concentration of your acid.

Fortunately, we do not need fuming nitric acid for precious metals refining - far from it. Also, azeotropic nitric has less of a problem with variable headspace pressure in your stock bottle due to dissolved nitric oxides.

 

[Yggdrasil]

If I recall correctly, the boiling point of nitric acid is about 83 degrees C. At that temperature, the nitric acid starts to decompose to water and nitric oxides, which reduces the concentration of your acid.

Fortunately, we do not need fuming nitric acid for precious metals refining - far from it. Also, azeotropic nitric has less of a problem with variable headspace pressure in your stock bottle due to dissolved nitric oxides.

That depends on the concentration.
The azeotrope is 68% and that is what you end up with when boiling it under normal conditions.

 

[Striker578]

If you make Fuming HNO3 you can dilute down to your requirements. If you know the temperature, have a graduate cylinder and a scale pretty accurately percentage to 70% are possible. ALWAYS add acid to water Slowly as it's Exothermic. .