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Ethanol dilution - (Apr/04/2007 )

Dear all,

I'de like to dilute ethanol 95° to ethanol 70° with water.

I remember it existe a Gay-Lussac table to do this according to the density of each liquide but I cannot find it anymore.

Could you please tell me how to proceed and/or give me an internet address or a book title to find this Gay-Lussac table.

Thank you in advance,



Hi! Den

To my mind your question need not this table. As I understand you can simply dilute 95 ethanol with water ( density 1 g\ml). Your task is not to make ethanol solution with exact conc. Yuo only need to dilute solution with known conc or in your case degree ( another dimension) So weight your volume of 95 solution you get y gram of your solution then add 0.36y gram of water .
If you can't weight (big volume) take this

94% ethanol - 758,6 g\l
96% - 769,3 g\l

make proportion and calculate 95% solution weight


V1 * M1 = V2 * M2

V1 = volume of ethanol you want to get
M1 = the concentration of ethanol you want to get, in this case is 70 %
V2 = volume of your stock ethanol, in this case is 95% , which is needed to be dissolved
M2 = the concentration of your stock ethanol (95%)


You want to make 100 mL ethanol 70% from ethanol 95 %
100 * 70 = a * 95
a = 7000/95 = 73.684

Take 73.684 mL or 73.7 mL or 74 mL (the precision depends on the purpose) ethanol 95% and add distilled water until total volume = 100 mL

-Miss L-

or, the easiest way, take 70 ml of 95% and add water to 95 ml.


QUOTE (mdfenko @ Apr 4 2007, 10:18 AM)
or, the easiest way, take 70 ml of 95% and add water to 95 ml.

Strongly agree with mdfenko! Sometimes our brain overload and build complex scheme!
Take it easy Dens!


i can remember when i was a newbie, my mentor asked me about the same question, yea i was thinking like mdfenko but, i also thinking may be my mentor asked me a more difficult question which answer is not so easy like this, so i was making complex the answer and then lastly he told me take it easy as circle point said here


-T. reesei-