[oaklandman]

which has stronger polairy, or is better for an extraction of a polar substance. 75.5% ethanol, or 99% Isopropyl alcohol? DONT BE OFFENDED IM A NEWB TO THIS SITE AND CHEMENSTRY!

[lemonoman]

If you ask me, it depends what the two are dissolved in.

If the ethanol is dissolved in water, the water is the most polar of all of those, and so it'll extract a polar substance no problem.

But if you just want to compare polarity of the two substances, here's the deal:  There's something called a "Snyder Index" for polarity.  Hexane, which is generally considered a very non-polar solvent.  It's Snyder Index is 0.  Water, which is really polar, has a Snyder Index of 9.

Anyways, on this scale, ethanol is a 5.2 and isopropyl alcohol (aka 2-propanol) is a 4.3

Therefore, an ethanol molecule is more polar than an isopropyl alcohol molecule.

For a list of other solvents and their polarity index, consult http://home.planet.nl/~skok/techniques/hplc/eluotropic_series_extended.html