Sciencemadness Discussion Board

Stock solutions and their concentrations

Scratch- - 3-3-2005 at 15:52

I have 10 bottles ordered (Along with some other chem stuff ;)) for stock solutions. I'm new to chemistry and when I am sufficiently advanced to make and handle superconcentrated solutions I would like to fill these bottles with the most concentrated solutions of the chemical that can be safely done. I was thinking about making the following solutions:

100% H2SO4
100% HNO3
?% HCl
?% NaOH
?% H2O2
?% NH3

The rest I'm not sure about if I will need them or not but I will put here anyway just so I have a chemical for each bottle (I'm a greedy chemical wanting person :D).

?% CO2
?% KOH
?% HBr
?% HI

Some of these solutions like the H2SO4 and HNO3 can actually be 100% and made from the condensed vapors (When I'm advanced enough to do that, which will be awhile). The NaOH and KOH can be the maximum amount that can be dissolved in water (Which is alot).

My three questions are:

1) I dont know if I will need the second group of solutions. What should I use for the solutions if I dont need the ones in the second group?

2) Where can I find the information on the concentrations that these specific gasses (HCl, HBr, HI, NH3 and CO2) can exist at safely with out fuming or vaporizing in my face?

3) What is the best concentration of H2O2? I would like it sufficiently strong so I can dilute into other solutions but still weak enough that it doesnt decompose in my face or in the cabenet (Which is in the garage, which gets hot sometimes).

I think some of these stock solutions will be really useful (And cool) to have. :P

The_Davster - 3-3-2005 at 17:28

Quote:
Originally posted by Scratch-
....HNO3 can actually be 100% and made from the condensed vapors... with out fuming or vaporizing in my face?


So you want 100% nitric and are worried about excessive fuming from some of the other solutions? 100% nitric will fume a great deal, hence it's other name, fuming nitric acid.:P

Hydrochloric acid has a maximum concentration in water of around 37% and this concentration does cause a great deal of fuming. More commonly is 31.45% HCl which is sold as muriatic acid, it still does fume, but it is not as bad as when it is more concentrated.

Concentrated ammonia solutions can be anywhere from 25-30%.

The concentration of the hydrogen peroxide depends on what you are going to be using it for. However, in general the highest concentration of H2O2 that is considered "safe" is 30% or 35%.

Scratch- - 3-3-2005 at 17:39

I thought fuming nitric acid was pure HNO3 with additional NO2 dissolved in it and it fumes because the NO2 can be liberated with motion/heat? On what conditions do HNO3/NH3/HCl fume?

I am using the H2O2 as a stock solution for making dilute solutions, I dont want it to decompose in my face, but its not like Im going to throw a chunk of copper or iron in it.

The_Davster - 3-3-2005 at 17:58

Quote:
Originally posted by Scratch-
I thought fuming nitric acid was pure HNO3 with additional NO2 dissolved in it and it fumes because the NO2 can be liberated with motion/heat? On what conditions do HNO3/NH3/HCl fume?
it.


You can have 100% nitric acid with no NO2 dissolved in it as well. This type of nitric acid is much more usefull than when there is NO2 dissolved in it.

HNO3, NH3, and HCl all fume when they are heated. This is applicable to all solutions that are composed of a gas dissolved in water since the solubility of a gas in water is inversely porportional to the temperature.

BromicAcid - 3-3-2005 at 18:26

Quote:
2) Where can I find the information on the concentrations that these specific gasses (HCl, HBr, HI, NH3 and CO2) can exist at safely with out fuming or vaporizing in my face?
I've found that the azeotropic concentrations of a gas dissolved in water and concentrations less then azeotropic show the least tendency to fume, well, there is at least a marked decrease in the fuming from azeotrope to just a few precent more. HCl has an azeotrope around 20% and it is realatively fume free unless you try to huff it.

Scratch- - 3-3-2005 at 18:28

Ah so if I can find the solubility of the gas in the liquid at any temperature if I know its solubility at at least two temperatures with the equation:

S = ConstA / T + ConstB

Where S is the solubility, T is the temperature, and the two constants can be found with two examples of S and T provided that they use the same measurements.

Is this correct?

EDIT: I posted this at the same time as Bromic Acid and now I realize that this wouldnt work at lower concentrations due to the azeotropes

[Edited on 4-3-2005 by Scratch-]