Expert: Henry Boyter - 1/11/2008

Question
My 9 year old has just gotten a Chem 2000 chemistry set - we're making litmus solution for experiments - instructions say to add a few drops of 'denatured alcohol' - I have rubbing alcohol at home and am not sure if they are the same - google results are very equivocal - can you help?

Answer
Denatured alcohol is ethanol (drinking alcohol) that has had a chemical added to it so that you can't drink it.  It is what is used in labs and commercial systems.  If you have some at home, grain alcohol works well.  Rubbing alcohol is a 70% solution of isopropyl alcohol and should work well enough for this, but try a little first.  The key is that the resulting solution should be clear (no solids).  If you see a few solids, filter it through a coffee filter.  If you see many solids, you need to get ethanol.  By the way, you can get denatured alcohol at hardware stores if you want to wait.  My hesitation is that the exact indicator you have will make a difference.

http://en.wikipedia.org/wiki/PH_indicator

http://en.wikipedia.org/wiki/Phenolphthalein

http://en.wikipedia.org/wiki/Denatured_alcohol