Thread: lab purpose

the purpose of this lab is... To separate multicomponent mixtures as a function of the ph of the solution. Can someone plz explain to me how do u separate multicomponent mixtures as a function of the ph? or like what does that mean.

This one intrigues me. I thought about it long and hard. I have a BS in Chemistry and I can never recall separating anything based on pH. As I think about it, it occurs to me that this is impossible. A bianary solution is not composed of two things with two different pHs but is a solution of one pH that is something of an average of their pHs. There is no way to differentiate pHs in solution. If you mix acid and base the acid donates a proton and the base accepts it. I think the purpose of your lab is misleading.

You'll have to be more specific, what it sounds like you're talking about is an acid/base extraction. In some cases with organic chemistry you raise the ph of your solution causing a reaction that turns your base to a salt that is then water soluble. You can reverse the process by making your solution basic. What your intended product is determines if you would discard the organic or aqueous layer. If your product is in the aqueous layer you can force your product out of solution by lowering the ph again. If keeping the organic, distill off your solvent.

I can think of a number of possibilities. The simplest methods take advantage of the fact that many ions are soluble in either acidic or basic pH's but they precipitate at the other end of the scale. This is a common method for dealing with inorganic compounds.

Another example is gel electrophoresis. A electric current is passed through a solution of mixed organic compounds. The pH of the solution determines how quickly each compound migrates through the medium and so they can be separated. Ion exchange chromatograpy or even simpler paper chromatography also relies on proper pH to separate components.