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Why doesn't silica gel dissolve in ethyl acetate when something like aspirin does. Both silica gel and ethyl acetate are highly polar. I though like dissolved like.

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    $\begingroup$ Neither aspirin, nor ethyl acetate are highly polar, but rather moderately. $\endgroup$
    – Mithoron
    Sep 11, 2015 at 0:00
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    $\begingroup$ @Mithoron, add the fact that silica is a network solid, so it does not dissolve in much of anything (except for what reacts with it), and you have good answer. $\endgroup$
    – Ben Norris
    Sep 11, 2015 at 1:31
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    $\begingroup$ If "like dissolves like" were the only rule, then your bathtub would get dissolved in water, together with much of your kitchenware. Oh, and your car would be gone completely, because it has both polar and non-polar liquids in it. $\endgroup$ Sep 11, 2015 at 6:26
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    $\begingroup$ Come on. Every empirical rule has its limitations. $\endgroup$ Sep 12, 2015 at 11:46
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    $\begingroup$ It is not incorrect, it is just limited. $\endgroup$ Oct 12, 2015 at 12:27

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Because (among other things) silica is not actually polar. Yes, theoretically a molecule of $\ce{SiO2}$ should have some degree of polarity to it. However, silica as a solid does not exist as single molecules.

Silica exists as a network of $\ce{Si}$ cations bonded together by $\ce{O}$ anions. One way of looking at it would be to say that each small bead of silica gel (or any other form of silica, glass or quartz) is one huge single molecule of silica.

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