51048

Hazards of gas evolution from nitric titration?  

January 25, 2009

What exactly is the gas or fumes given off during titration of nitric solutions ? I work in an aluminium anodising plant, in the lab as a lab tech. My interest is one of an health concern. Just how nasty / health affecting is the gas/fumes. There is no ducting taking the fumes away, and I do these checks 6 times a shift. Any one help ?

Steven G
Lab Tech - England

Steven,

You are going to have to give us some more detail:

What strength is the nitric acid? If it is a high strength the fumes that are coming off may be just fumes from the niric solution itself, not from any reaction in the beaker.

Is it a pure nitric solution or is it mixed with other chemicals?

What are you titrating with? Is it a straight acid-base titration? If it is a straight acid-base then the results will be salt plus water. So if you are titrating nitric with caustic solution your resultant products are simply Sodium nitrate and water. If you are titrating with something other than a base we need to know what it is before anyone can tell you what you are producing.

Brian Terry
Aerospace - Yeovil, Somerset, UK

The samples are so small that there is very little problem in doing a titration, especially if it has been diluted. Large samples are (or should be) a thing of the past. A proper 1 ml sample is as valid as a 10 ml sample with a smaller burrett.
most of the material that would give a gas is dissolved back into the water or normally is in an ionic and not gas form.

James Watts
- FL

I suspect Stephen is analysing nitric acid in his chemical polishing solution where he adds phosphoric acid, warms and titrates slowly with ferrous sulphate to a permanent brown end point.
Considerable nitrous fumes are given off during the titration and it should be done under a fume hood and definitely not breathed in.

Geoff Whitelaw
- Port Melbourne, Vic., Australia

Hello,
If fumes are emanating to the extent of creating discomfort, it is better the titration is carried out inside a fume cupboard.
S.Ramajayam

Subramanian Ramajayam     plating chemist Bangalore, Karnataka, India