Miscibility

[fishtea]

I read a good bit on miscibility and couldn't find the answer to this question.

Is it only highly polar and non-polar solvents that are immiscible in each other or are any polar and non-polars immiscible?

[RAOVQ]

alcohols will happily mix in both oil and water. organic acids too. it's a nice rule of thumb but it isn't 100%

[fishtea]

Alcohols are polar protic solvents like water though.
http://en.wikipedia.org/wiki/Solvent...ommon_solvents

[RAOVQ]

i don't think i understand the original question.

[fishtea]

I was wondering if you have two solvent which are polar opposites like water and hexane can you assume they are immiscible or are there other reasons for two solvents to be immiscible with each other?

[Graah]

The basic rule is "Like dissolves like", meaning that polar things will dissolve in a polar substance and non polar in a non polar.

The reason some things, like acetone, can mix evenly with either polar or non polar is that they have a polar end, but are mostly non polar, I think.

There is also something called Van Der Waal's Forces you should look up, cause I'm not gonna explain it.

[psychojoe]

do straight-chain alcohols become increasingly insoluble in water, and decreasingly so in non-polar solvents, as their chain length increases?

[yixil]

Originally Posted by psychojoe

do straight-chain alcohols become increasingly insoluble in water, and decreasingly so in non-polar solvents, as their chain length increases?

I believe so.

Long-chain lipids with polar ends, such as phospholipids, tend to form bubbles with the polar end on the outside and the nonpolar tails on the inside.

[fishtea]

So are all organic solvents immiscible in water? For instance would naptha be insoluble in water forming two layers when mixed?

[RAOVQ]

you can't make a blanket statement. some alcohols are water soluble, some are not. organic acids are, as are some amines. this is due to chemical reactions, but to ignore chemical reactions and try to make a blanket statement about polarity and solubility is oversimplifying and ignoring the actual chemistry.