Editing Encyclopedia:Reference Desk archive unanswered (section)

== Chemical Reaction of Sodium Carbonate Dissolving Oil Stain ==

I would appreciate if someone with a chemistry background could help me.  I plan to do a science fair project where I will dissolve just sodium carbonate (washing soda) in hot water to remove an olive oil stain from cotton fabric.  No other detergents or laundry boosters will be added and the water is soft and the sodium carbonate will not have to worry with "neutralizing" the magnesium and calcium deposits, etc.  I plan to use different amounts of the sodium carbonate to see if a larger amount will dissolve the stain faster.

My dilemna is that per my research via the internet, science dictionaries and even "Wikipedia's" archives, I could not get an explanaation on the chemical process.  I do not have access to university libraries and the public library is limited in their science/chemistry information.  Either none was offered or advanced for my purposes.  I  have had some chemistry, but will not have a complete chemistry unit until next year in 10th grade.

Per my research, several scenarios should occur:

1)  the sodium carbonate should create an emulsion that will list  the stain from the fabric;

2)  this process is the result of hydrolysis; and

3)  a mild saponification could occur and convert the stain into "soap."

Your input and help would be greatly appreciated.

Thank you.

--Scott

:First thing, I'm just a student studying chemistry, but anyway here is the outline of the chemical process involved.

:The order in your list is wrong, actually it is 2,3,1(or 3,2,1? not sure on the hydrolysis).

:Firstly, [[sodium carbonate]] dissolve in water to give [[alkaline]] solution
<math>\mbox{Na}_2\mbox{CO}_3+\mbox{H}_2\mbox{O}\to2\mbox{Na}^++\mbox{HCO}_3^-+\mbox{OH}^-</math>
, because of prescence of Na<sup>+</sup> and OH<sup>-</sup> ions.

:Then, when given extra energy(e.g. by heating or using hot water as in your case), [[saponification]] occurs, in which the triester is changed into glycerol and [[soap]].

:Finally, the soap [[emulsify]] the oil left. The hydrocarbon chain dissolve in the oil well, while the ion part dissolve in the water. Water molecules attract the ion part and thus the oil stain is lifted off the surface. Then the droplets can't come together again due to repulsion between ions of the soap.
:--[[User:Lemontea|Lemontea]] 15:09, 23 February 2006 (UTC)