Jump to content

hno3 - determning conc.


akcapr

Recommended Posts

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?

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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?

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.