hno3 - determning conc.

[akcapr]

If i was to make nitric acid via the sulfuric acid- potassium nitrate method, how would i accurately figure out the concentration of the nitric acid knowing the amount of liquid the NO2 will dissovle in,the amount of H2so4 and its conc., and knowing amount of potassium nitrate, and assuming all the gas will dissolve?

 

also, just making sure: the colder the water the better the gas will dissolve in it, correct?

[raivo]

[math]\ce{H2SO4 + KNO3 -> KHSO4 + HNO3}[/math]

[akcapr]

sometin like an equation would help. I know the reaction, just how to figure out the concentration depending on the amount of water it dissolves in.

[budullewraagh]

i strongly advise you to not make nitric anhydride. it comes back to haunt you later in life

[Silencer]

how would one remover the potassium sulfate after the above reaction? I thought all sulfates were soluble...

[akcapr]

i wasnt gonna make it purposely, how do i better make nitric acid then? and kno how to figure the conc. I was think no2 would come out due to the heat

[H2SO4]

you could tr y titration. Heres a link to a page that shows procedure. Ive never performed titration but iv read about it in books.

 

http://en.wikipedia.org/wiki/Titration

[Fortuna]

Actually, simply measuring the density with a good volumetric column and an accurate scale will give you a pretty good idea of the concentration you have.

 

The titration method of course works a bit better and is admittedly more accurate. However, be sure you don;t have any unreacted H2SO4 in there.

 

If you know the purity of the H2SO4 and KNO3 you started with, you should already have a pretty good idea of what the concentration is anyway.

[akcapr]

what about the nitric anhydride thing bulldewraagh said?

[budullewraagh]

it's scary and it will cause permanent respiratory failure. if you survive the initial pulmonary edema, 10 years from now you'll feel it coming back; you'll feel asthmatic, you'll be susceptible to bronchitis and pneumonia, etc. need i say more?

[akcapr]

how would i make nitric acid (w/ sulfuric acid kno3 method) without making that nasty stuff?

[budullewraagh]

you probably wouldnt...

[akcapr]

reallly? what about this http://www.totse.com/en/technology/science_technology/nitric.html

 

and this

 

http://www.skepticfiles.org/new/133doc.htm

[raivo]

it's scary and it will cause permanent respiratory failure. if you survive the initial pulmonary edema, 10 years from now you'll feel it coming back; you'll feel asthmatic, you'll be susceptible to bronchitis and pneumonia, etc. need i say more?

 

May well be true but if you do not inhale it in remarkably quantities nothing will happen. Nitric anhydride is not that mysterious substance. Anyone who deals with nitric acid (like some artist for example) will inhale it occassionally. Nitirc acid, even diluted fumes, that gas.

 

To make nitric acid safely you need good fume hood or have to synthesise it outside. You still have to be extra cautious not to inhale any fumes. Amount of H2SO4 has to be such that there would never be any dry nitrate. Otherwise you may decompose nitrate by heating and if you are especially unluky that process may decompose you.

[akcapr]

how would i get the right amount of h2so4 so theres no dry hydrate?

[budullewraagh]

akcapr, if you do that reaction cold with not very conc sulfuric acid, you could conceivably avoid the nitric anhydride problem. still, it's tricky and you will be left with a very impure product.

 

raivo, nitric anhydride is just as bad as i described

[raivo]

I said "dry nitrate"! You just have to pour so much H2SO4 that all nitrate is wet and you have to watch it stays wet during the process. Otherwise you may decompose it by heating.

[akcapr]

so i would just add enough h2so4 too cover the nitrate and kkep it "wet"? Also, if i would heat would i heat it boiling or just below. Becasue the h2so4 could evaporate/ boil and the vapor would dissolve in the liquid and contaminate my acid, correct?

 

and, even if i did get nitric anhydride couldnt i (safely) collect it and dissolve it in water?

[raivo]

H2SO4 will not evaporate below 200C (or even more). You have to heat over 100C, boiling water bath is not hot enough. Anhydride dissolves so well that you even can not put tube into water because liquid will instantly rise up by tube into your boiling flask.

 

Experiment with few milliliters in test tube and ONLY if you get everything working go to greater amounts.

[budullewraagh]

yes, you could collect and dissolve your nitric anhydride, but again, it's bloody scary. if you HAVE to do this, use PTFE tubing; just about anything else will be oxidized

 

h2so4 at high concs will fume the anhydride, SO3, a white gas. it makes you choke. i had a fun experience with that once.

[H2SO4]

reallly? what about this http://www.totse.com/en/technology/science_technology/nitric.html

 

 

 

 

Never listen to people on totse. There a bunch of dumbasses.