NaCl precipitate

[StijnR]

Hi everyone,

 

I was wondering if anyone could help me with the following problem. We are supposed to make an ester by heating up an alcohol, an organic acid and sulfuric acid together. When the reaction is complete, we add a saturated aqueous solution of table salt to aid in the separation of the organic and inorganic layers. A precipitate of table salt will form when this is done. My question is, why does this occur? Is it maybe because the organic molecules interfere with the water's ability to interact with the salt's ions?

 

Thanks in advance!

Edited April 22, 2012 by StijnR

[Bioc]

Mmm well you add saturated table salt, so when you are done heating, the solvating capacity of water becomes lower. Or maybe it means that when you are done shaking you have to let the suspended particles decant.

 

When I was at the lab I just added saturated salt water until the emulsion broke, then proceeded to separate the phases, but I don't remember seeing a precipitate (I was extracting plant pigments, though).

Edited April 23, 2012 by Bioc

[John Cuthber]

Hi everyone,

 

I was wondering if anyone could help me with the following problem. We are supposed to make an ester by heating up an alcohol, an organic acid and sulfuric acid together. When the reaction is complete, we add a saturated aqueous solution of table salt to aid in the separation of the organic and inorganic layers. A precipitate of table salt will form when this is done. My question is, why does this occur? Is it maybe because the organic molecules interfere with the water's ability to interact with the salt's ions?

 

Thanks in advance!

Essentially, yes.

The leftover alcohol mixes with the water and the mixture doesn't dissolve the salt as well as clean water does.

[StijnR]

Thanks a lot for the replies!