View Full Version : Shelf Life of Chrome Alum?

07-26-2010, 11:55 AM
Hello PE and Everybody Else,
Recently I discovered an overlooked bottle of 10% chrome alum. It has been in a brown glass bottle at ambient temperature for at least a year. Should I just dispose of it?

07-26-2010, 12:08 PM
i have been thinking the same thing; however, mine is some shade of purple, which leads me to think "over the hill"

07-26-2010, 05:14 PM
I may be "over the hill", but I'm not purple yet! (big grin)

07-26-2010, 09:20 PM
me too bill and not only that i don't even have blue hair, let alone purple

Photo Engineer
07-26-2010, 09:41 PM
If it is purple and dry, then it is still good. If it is in solution and in the fridge and purple it is still good. If it is any other color or has a precipitate it is bad. It should resemble grape juice if dissolved in water at 10%.

I have kept it dry for several years with no harm.


07-27-2010, 07:50 AM
it is dry, thanks as i was going to get rid of it. Have been putting together a lot of dry chemicals as we haven't done the "mad scientist" thing for sometime with the students, but certainly didn't want to offer something that would be worthless.