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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

January 29, 2009
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
January 29, 2009
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
February 22, 2009
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
May 28, 2009
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
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Subramanian
Ramajayam
plating chemist
Bangalore, Karnataka, India
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