blood vs lipid solubility, halothane vs NO2

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reburbia

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1) Higher polarity = higher blood solubility
2) Lower polarity = higher fat solubility

However First Aid says NO2 is less soluble than Halothane in both blood and fat??? Someone please correct my premises and settle this paradox

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As a cation, nitrogen dioxide is a linear molecule, which makes it less soluble in the blood. As a radical species or anion, it is a bent molecule that bears charges that are stabilized by resonance, which makes it less soluble in fat. Solubility is a relative concept. A compound that is generally considered insoluble in water might still be soluble in water with enough volume of the solvent. One might just need the whole Pacific Ocean to dissolve a small amount of the compound. Halothane and nitrogen dioxide may both be insoluble in either solvent. Nitrogen dioxide may just be more insoluble.
 
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Thank you for the response. Ok so you're saying it's not just about polarity (charges), but it is also about the shape of the molecule?

My whole life as a student I was taught that polar objects dissolve more readily water/blood, and nonpolar objects dissolve more readily in fat. It just seems weird that Halothane is (relatively) more soluble than NO2 in BOTH blood and fat. I just assumed if you had a relatively easier time dissolving in one, you would have a relatively more difficult time dissolving in the other.
 
Shape influences symmetry, which influences polarity because there is an uneven distribution of electron density if the molecule is not perfectly symmetrical.

Your teachers didn't lie to you. For the MCAT, your logic regarding polarity and solubility should suffice.
 
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