Is there a litmus test or some other test which can determine if alcohol is present in an unknown substance?

Answer 1

1.000 ml Acetic anhydride will react with any alcohol group, with heat (~130 C) for 30 min in a sealed vial. Cool, then add water, then titrate with standardize base (.5000 KOH) with phenyphlathein as indicator titrate (first sign of pink is endpoint, dark pink is over titrated)

Run a blank (1.000 ml acetic anhydride then add 1 ml water) cool, add phenylphalein, should run about 42.5 mls of .5000 KOH

(Blank titration-Sample)* 56.1*Normality KOH/sample weight in grams

If blank=sample volume then increase your sample weight significantly and repeat. You want the sample to run about 70 % of the blank for best number (if blank=40mls .5000 KOH, then sample=25-30 mls)

If your looking at very small amounts of alcohol, you might consider GC analysis for ppm.

Answer 2

What is a spot test for alcohol?

Is there a litmus test or some other test which can determine if alcohol is present in an unknown substance?
Mike Jeffery

The classic test for alcohols uses chromic anhydride (CrO3) in sulfuric acid solution. Within seconds after contacting a sample containing alcohol, the solution turns from clear orange to cloudy blue-green. Be careful- chromic anhydride in acid is extremely corrosive, poisonous, and carcinogenic.

You can detect grain, wood or rubbing alcohol with the "iodoform test". Treat the sample with iodine and sodium hydroxide; if these alcohols are present, you get a cloudy yellow precipitate (CHI3). The test can be fooled by some ketones (for example, nail polish remover will give a positive test because it contains acetone).

Author: Fred Senese [e-mail]

Answer 3

it smells like alcohol.