[aeacfm]

every time i dissolute NaOH (but in high concentrations) some fumes generated which make me cant breath !!
what are these fumes

[Grundalizer]

1.  What are you putting in what?  NaOH in Water?  NaOH with a metal?

2. Who is the picture of your profile pic?

3.  I'm guessing it's hydrogen.  If you can smell it though, then it's not hydrogen.

[Mitch]

definitely not hydrogen. Naoh plus water releases heat. The fumes you see coming off is just water vapor that is now very basic.

[bromidewind]

2. Who is the picture of your profile pic?

That would be Jabbir Ibn-Hayyan, otherwise known as the father of alchemy.

As for the fumes, as Mitch said, it's basic (as in pH) fumes. You're having difficulty breathing because it's irritating the mucus membranes in your nose, throat, and mouth. If you inhale a lot, get some fresh air or go to a hospital. You can check the MSDS here for further information.

[aeacfm]

2. Who is the picture of your profile pic?

That would be Jabbir Ibn-Hayyan, otherwise known as the father of alchemy.

that is an answer to "Grundalizer "

 

[aeacfm]

definitely not hydrogen. Naoh plus water releases heat. The fumes you see coming off is just water vapor that is now very basic.

it is of pleasure to me that you reply me Dr/Mitch

you mean basic water vapor or simply vapor of NaoH solution or there is difference

[Grundalizer]

It depends what you are mixing it in.  If it's NaOH in water you shouldn't get any fumes at all, unless you are dumping mass quantities of NaOH into a small amount of water, and then perhaps you might get aqueous NaOH in water droplets vaporizing.  If you are mixing it in water WITH metals like Aluminum or the such you'd also get H2 gas along with probably vaporized water with aqueous base in it, although I've never had a problem dealing with NaOH solutions.  It's usually NH4 OH that smells and is harsh to breath

[aeacfm]

i remember i used like what you noticified "large amounts of NaOH in small amount in water"
but i will try small amount in large water

[Stepan]

aeacfm, thank you for the good question. It sounds like quite simple, but this is one of few "mysterious observations" I could not understand from the time my high school years. 

If this fume is just water fog, why it is formed when you dissolve Sodium Hydroxide but there is no fog when you dilute Sulfuric Acid (also exothermic reaction)?