Is concentrated HCl (12M) a liquid and a gas?

[AMan24]

I just remembered that in my lab from a few months ago, the 12M HCl we used was "evaporating" or producing gas, similar to dry ice in water but no where near as much vapor. I'm just curious, is concentrated HCl usually like that or was the acid contaminated?

 

[DrClaude]

"Is concentrated HCl (12M) a liquid and a gas?" Neither, its a solution.

All liquids, even much below the boiling point, will be combined with a vapor phase, where molecules will go into the surrounding gas (although in many cases the vapor pressure can be quite low).

With concentrated hydrochloric acid, you end up with nasty acid fumes that you should not breathe. They can do serious damage to the respiratory system.