Yellowing of Nitric Acid

[mclaran10]

Since I received a bottle of concentrated nitric acid (it's a plastic container) from Elemental Scientific some time ago, the acid has begun to assume a slight yellow color. Is this due to reaction with the container? the air? Is this something to be concerned about? I guess I'm not really sure what is going on chemically. I don't have a spare glass container for the acid, but I suppose I could transfer my concentrated HCl to the plastic bottle and put the nitric acid in the glass HCl bottle. What would you recommend?

[thompson]

It's probably not the bottle. It's not uncommon for concentrated nitric acid to assume a pale yellow color, which is caused by nitrogen oxides.

[mclaran10]

Thank, I was a bit worried that the bottle was in danger of leaking or that pressure could build up inside.