Can I increase the percentage of NAOCL?

[oerd]

If I buy domestic NAOCL with an 3% of NAOCL, is there a way to decreae the amount of water in order to increase the concentration of hypochlorite of sodiun?

 

thanks in advance

[John Cuthber]

Yes.

[oerd]

Thanks for the answer John

Could you explain me the best way to do increase the concentration of NAOCL

How can I eliminate water, but just water in a solution of NAOCL at 3%?

[theoriginal169]

you shuold know exact boiling point at your cond. both water and your chemc. then collect the vapor .first heat.

[UC]

you shuold know exact boiling point at your cond. both water and your chemc. then collect the vapor .first heat.

 

Except that sodium hypochlorite is a nonvolatile salt. Heat and concentration drive the disproportionation to chlorate and chloride and IIRC, it's unstable above about 20%.

[theoriginal169]

Except that sodium hypochlorite is a nonvolatile salt. Heat and concentration drive the disproportionation to chlorate and chloride and IIRC, it's unstable above about 20%.

i didnt know that its interesting so how he can solve his problem.

[John Cuthber]

You can remove some of the water under vacuum, but the stuff will tend to decompose.

[louis wu]

Just use a desiccator jar to remove the water.

A beaker of conc sulphuric acid can be used as a replacement for normal desiccants. The conc acid will remove water quicker than normal desiccants.

[John Cuthber]

"The conc acid will remove water quicker than normal desiccants"

When the water leaves the solution, how does it know to hurry up because there's some sulphuric acid out there?

[louis wu]

"The conc acid will remove water quicker than normal desiccants"

When the water leaves the solution, how does it know to hurry up because there's some sulphuric acid out there?

Conc sulphuric acid has an affinity for water that is unmatched.

The use of this acid will result in lower humidity within the desiccator vessel, which in turn results in faster evaporation from the solution. The speeding effect may not be spectacular (depending on which desiccant we are replacing) but is there.

 

I have actually used conc sulphuric to regenerate desiccants such as silica gel, calcium chloride or calcium sulphate.

[John Cuthber]

"Conc sulphuric acid has an affinity for water that is unmatched."

 

Phosphorus pentoxide will strip the water out of concentrated sulphuric acid and convert it to sulphur trioxide.

 

Most people find it cheaper and more convenient to regenerate desiccants like silica gel in an oven.

 

Incidentally, as soon as the acid picks up any water it stops being nearly as good a desiccant.

Other drying agents can pick up more moisture without losing so much of their power so, even if H2SO4 was quicker at first it may lose ground in the end.

 

If you want to speed things up use a vacuum desiccator. Also it's not generally a good idea to use sulphuric acid as a drying agent because it's rather nasty stuff to work with.

[DeepSpace]

Just use a desiccator jar to remove the water.

A beaker of conc sulphuric acid can be used as a replacement for normal desiccants. The conc acid will remove water quicker than normal desiccants.

no,H2SO4 will react with NaOCl to get chlorine gas free

[louis wu]

"Conc sulphuric acid has an affinity for water that is unmatched."

 

Phosphorus pentoxide will strip the water out of concentrated sulphuric acid and convert it to sulphur trioxide.

 

Most people find it cheaper and more convenient to regenerate desiccants like silica gel in an oven.

 

Incidentally, as soon as the acid picks up any water it stops being nearly as good a desiccant.

Other drying agents can pick up more moisture without losing so much of their power so, even if H2SO4 was quicker at first it may lose ground in the end.

 

If you want to speed things up use a vacuum desiccator. Also it's not generally a good idea to use sulphuric acid as a drying agent because it's rather nasty stuff to work with.

 

Well yes in P₂O₅ you have the only chemical desiccant that rates above conc H₂SO₄ in this table.

http://www.mallbaker.com/techlib/documents/americas/3045.html

But I do not see it as a good choice for this case, as it a severe toxic dust hazard, and tends to form a coating that inactivates itself.

 

Incidentally are you sure that P₂O₅ will strip water from conc H₂SO₄ if they are in separate beakers in the same desiccator rather than in direct contact? I endorsed H₂SO₄ because it will be found in most labs whereas P₂O₅ or molecular sieves will not be.

 

Actually for staying power as a desiccant, conc sulphuric is tops in terms of g/g water capture.

Of course silica gel is most conveniently regenerated in a furnace, all our furnaces were in use at the times I have used conc sulphuric to regenerate desiccants.

 

From comparing the two MSDSs conc sulphuric is a less hazardous chemical to use. Anyone with some chemical experience will know how to use H₂SO₄ safely, and any chemicals lab will have the correct equipment. P₂O₅ appearing as an innocuous white powder can catch people unawares and contamination often happens without people realising at the time.

 

Of course if the user is inexperienced with chemicals, has no safety equipment, and is working in a shed at the end of their garden then conc sulphuric is a dangerous chemical. Under such circumstances P₂O₅ is an even more dangerous chemical to use and we would be more likely to see evolution in action.

 

Finally I am unsure if NaOCl solution is suitable for use in a vacuum desiccator it tends to decompose.

[Justonium]

Just use sodium hydroxide as a dessicant, it's easy to come by and works very well. Also, there's all this talk of which dessicant is better, all of them lower the vapor pressure of water to near zero, so the real solution to increasing dessication speed is to increase the surface area of the dessicant and optimally to increase air flow.

[John Cuthber]

All this talk of what's the best drying agent isn't really important here. You are trying to remove bulk water so even table salt will do as a desiccant.

As has been pointed out a number of times the NaClO isn't stable so you will lose a lot of it no matter how you try to dry it. You certainly won't end up with a pure solid.

 

"Actually for staying power as a desiccant, conc sulphuric is tops in terms of g/g water capture. "

Actually it's not. Both sodium and magnesium sulphates will absorb roughly their own weight in water before they are exhausted. 50% sulphuric acid isn't much of a drying agent.

The question of whether sulphuric acid is more of a hazard than P2O5 isn't relevant here. You don't need to use either. The reason I mentioned it was simply to illustrate that your assertion that "Conc sulphuric acid has an affinity for water that is unmatched." isn't correct. I could have chosen a number of other desiccants like sodium wire. All strong dehydrating agents are dangerous because we are mainly water.