Salting Out Ethanol From Water - Nc State University (Page 2 of 2) in pdf

Salting Out Ethanol From Water - Nc State University Page 2

NCSU – Dept. of Chemistry – Lecture Demonstrations

Organic Chemistry

Discussion: Water and ethanol are miscible due to their existing intermolecular

forces, the strongest of those being hydrogen bonding. As an electrolyte (in this

case K

) is added to water, the solvation of the electrolyte makes water

unavailable to hydrogen bond with ethanol. The solubility of ethanol decreases

as a result of the lack of hydrogen bonding interactions with water. As a result,

the organic dye which was initially yellow due to the acidic solution is absorbed

into the organic phase with ethanol and becomes blue.

Safety: Ethanol is flammable and should be kept away from any open flames.

Disposal: The resulting mixture should be flushed down the drain with plenty of

water.

References:

Shakhashiri, B. Z. In Chemical Demonstrations: A Handbook for Teachers of

Chemistry; The University of Wisconsin Press: 1989; Vol. 3, p 266-268.

Smith, E. T. Chem. Educator 1997, 1, 1.

Video:

Salting Out Ethanol From Water - Nc State University Page 2