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Needed to make up 2L of iodine solution (for prac exam) and consulted the laboratory and followed the recipe as per page 75. It said to make 24hrs before as iodine is slow to dissolve. So I left it over night and covered it with some alfoil, so crap wouldn't fall into the solution. Came in this morning to check on it, and the alfoil had disintegrated Why????????????? Should I not have covered it perhaps?
Use Gladwrap next time! :clap3:Thanks for the tip!
What are you using Iodine for? as Starch Indicator needs to be brown, as cell stain on microscope slides, needs to be diluted till very pale yellow.
I think, you can still use your solution. It is only used to colour starch or cells, the Al foil will not interfere.
Not sure, if glad wrap would work.
The fumes from I must be very reactive.
There are different concentrations of I, I usually prepare the stock soln and then dilute.
Good luck Sassi
lada
Hi Sassi
I did something similar. I made my solution and left it on a painted bench surface and covered it with a bucket. When I came in next morning and lifted the bucket it had left a big ring between the bottle and bucket! I still used it and it was fine.
I still have the stain after endless wipe overs.
I now use glad wrap and stand the amber bottle in a large brown paper bag no more stains.
I also store the bottle in a brown paper bag as well seems to last longer.
Hope that helps.
Thanks you guy Thought I'd have to chuck the whole thing out...
Bindi, I have had some very stubborn iodine stains on my benches, one day I dropped a bottle of vitamin C powder on the stain (being the clutz that I am) and miraculously the stain vanished when i started wiping the vitC off So now thats what i use, try it
If the iodine solution also has potassium iodide in it, dissolve the KI first in a small amount of H2O, then put the iodine into that. It will dissolve into the solution easily then make up the dilution. Iodine dissolves easily into a concentrated KI solution.
I got this hint off the internet and it works
Julie
Kirrawee High
I make my iodine solution up in the same opaque plastic bottle it is stored in, giving myself a day or so before it is needed.
Im at home so can't remember the actual amounts but I make up the Potassium Iodode solution in the beaker pour that into my bottle and then add the iodine straight into the bottle. I then put the lid on and every time I go past the bottle for the next day or so I give it a good shake to help disolve the crystals. Not too scientific but it always worked for me. I decided to try this one day after spending hours stirring and trying to disolve the iodine. This way I can leave it overnight and it is already in its dark container.
Had an emergency last week (forgot to check if I had iodine solution made up). With an hour till classtime, and reasonably desperate, I made up 7.5g of potassium iodide in a small quantity of water (less than 50ml) and added 1.5g of iodine crystals and stirred the solution. The iodine broke up with some crushing assistance and lots of stirring until there was no iodine solid left and I did let it sit for short periods of time to let the potassium iodide do its thing. I then made the solution up to 500ml. Filled the dropper bottles and voila!!! Then the teacher cancelled the prac.
As they do!!
I had a grovelling teacher on Mon morning Pleeeease, could you make up...
So I felt sorry for her and spend first 2 periods preparing the prac, only for her to come after class to tell me;"we did not get around doing it.."
I had murder on my mind
lada
Don't you just love'm They must all be the same, I have 3 Year 10 pracs, written in for today, "hello year 10 are out all day. It's been timetabled for weeks. I remembered now only 2 for today
Why????????????? Should I not have covered it perhaps?
I still used it and it was fine.
Thought I'd have to chuck the whole thing out...
So now thats what i use, try it 
