can nitric acid go off?

[medusa]

I'm trying to etch some pebbles and it's just not happening. I can't see any bubbles or anything. I have even put them in a small dish of the neat acid. no reaction. I'm sure last time I used it, there were bubbles.


any suggestions? I want to get them finished and in the post on saturday, but at this rate it's going to take all week.

[PureGold]

Have you kept the nitric acid in a well sealed container, as I believe it tends to be hygroscopic, drawing moisture out of the atmosphere and thereby diluting itself.

[medusa]

I thought it was well sealed, but clearly not. I've resorted to using ferric again.

[Joe]

Concentrated nitric reacts with oxygen in the air to produce a brown gas, nitrogen dioxide. It is very acrid and extremely dangerous; you would certainly notice it.

Even if the bottle is tightly sealed, if there is air in there it will decompose at room temperature and turn yellowish.

If it isn't yellowish and you haven't noticed the poisonous gas, then something else has happened.... well worth investigating!

[Kwant]

I read up on nitric acid today and it gave me the willies, I will not be touching the stuff.

[medusa]

Concentrated nitric reacts with oxygen in the air to produce a brown gas, nitrogen dioxide. It is very acrid and extremely dangerous; you would certainly notice it.

Even if the bottle is tightly sealed, if there is air in there it will decompose at room temperature and turn yellowish.

If it isn't yellowish and you haven't noticed the poisonous gas, then something else has happened.... well worth investigating!

hmmm, well it's still completely clear, but I obviously open it outside and well away from my face for the reasons I'm sure Kwant is well aware of after reading about it. but I did get it well over a year ago.

So i have no idea what is up with it. it reacts if I put bicarb in it but even the undiluted stuff has done nothing to a snip of silver wire I put in.