Topscore T1 Chem section question 63

[hokie4life]

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I know this is not like the hardest question ever or anything but when I see miscibility I think density so how come the answer is polarity? I understand that with polar-polar molecules they will bond closer so you get higher density? So then shouldn't the answer be density and not polarity...i can see both being right but I just think density first for misciblity explanations....


so why is polarity the better explanation for why molecules can be miscible or not?

please help😳

 

[Toothguy80]

because two things are miscible when they are alike,

Oil wont dissolve in water, because they are not alike..

Two things that are polar will mix with eachother, like alcohol and water, carboxylic acid and H2O.

PCl4, anything like that is non-polar and is bad, thus will not mix with H2O.

Just think Miscibility = polarity = how well two liquids mix with one another.

😎😎😎😎😎😀😛

 

[KEC029]

I think of

solubility as solvent - solute interaction (ie. H2O - NaCl)

miscibility as solvent - solvent interaction (ie. H2O - Oil)

so polarity should matter for both.
but density should only matter for solubility.

 

[hokie4life]

firstly, thanks for the awesome explanation so far! i get how polarity can be the answer now but can't density be the answer too!? because aren't things immiscible when they have different densities like water and oil?

i just don't understand why you can't use density to explain miscilbility, I feel like i always learned those together so still want to pick polarity and density as the answer 😱