Testing for the type of alcohol

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Discussion Overview

The discussion revolves around methods to test a mixture for the presence of ethanol or isopropyl alcohol. Participants explore various experimental approaches, including salting out and density measurements, while considering the practicality and effectiveness of these methods.

Discussion Character

  • Exploratory
  • Technical explanation
  • Experimental/applied

Main Points Raised

  • One participant suggests using a salting out experiment to determine whether the mixture contains ethanol or isopropyl alcohol.
  • Another participant proposes consulting density tables for ethanol and isopropyl alcohol mixtures with water, emphasizing the importance of knowing the type of density measurement (w/w, v/v, or v/w).
  • A participant acknowledges the simplicity of using density measurements and expresses gratitude for the suggestion.
  • Concerns are raised about the small difference in density between the two alcohols, suggesting careful measurement is necessary.
  • One participant questions whether smelling the alcohol might be a simpler method for differentiation.
  • A later reply clarifies the salting out method's potential effectiveness, asking if the separation indicates isopropyl alcohol and if ethanol would not separate.
  • Another participant encourages conducting both the salting out experiment and density measurements to compare results.

Areas of Agreement / Disagreement

Participants express various methods for testing the alcohol type, with no consensus on the best approach. Some support the salting out method, while others emphasize density measurements, indicating multiple competing views remain.

Contextual Notes

The discussion includes assumptions about the effectiveness of the salting out method and the accuracy of density measurements, which may depend on specific conditions not fully explored.

bigshlomi
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TL;DR
How to test if the alcohol I have (70% alcohol and 30% purified water) is ethanol or isopropyl
How can I test if the mixture I have contains ethanol or isopropyl? Will a simple "salting out expuriment" work (adding salt and seeing whether the mixture separated or not)? Or is there a better way to check?
 
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Ethanol and isopropyl alcohol mixtures with water should be common enough to find a density table for different concentrations online (make sure if it's w/w, v/v, or v/w) and simply doing the math.
 
Mayhem said:
Ethanol and isopropyl alcohol mixtures with water should be common enough to find a density table for different concentrations online (make sure if it's w/w, v/v, or v/w) and simply doing the math.
That's... So simple I'm ashamed I haven't thought of it myself... In any way, Thank you!
 
The difference in density isn't very large so you would need to measure carefully.

Wouldn't it be easier to smell it?
 
JT Smith said:
The difference in density isn't very large so you would need to measure carefully.

Wouldn't it be easier to smell it?
Well then I should rephrase the question: I want to try the salting out method of purifing isopropyl as a fun first expuriment. Is this also good to check if the alcohol is isopropyl (if it seperates) or ethanol (if it doesn't)?
 
If one salts out and the other doesn't then the answer would be yes, wouldn't it? Or are you asking whether or not ethanol can be salted out with sodium chloride?

Since the whole point seems to be experimentation why not do both experiments? Add table salt to an isopropanol/water solution and to an ethanol/water solution and see what happens.
 
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