AAMC 4, Solubility Question

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davcro

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Why doesn't the carboxylic acid groups on camphoric acid hydrogen bond with 4-aminobenzoic acid, thus increasing the melting point?
 
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mcloaf

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There will still be some hydrogen bonding, but that won't necessarily increase the melting point. The issue is whether or not any hydrogen bonding between 4-AB and camphoric will be stronger or weaker than the h-bonding of just pure 4-AB. Generally pure substances pack together better and bond more tightly, so while the camphoric acid will hydrogen bond with 4-AB, this bonding won't be as strong as if your sample contained only 4-AB and will thus lower the melting point.
 

MedPR

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Why doesn't the carboxylic acid groups on camphoric acid hydrogen bond with 4-aminobenzoic acid, thus increasing the melting point?

Mixtures must have a melting point between the mp of the two pure substances.
 

pfaction

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I didn't even say that, a pure compound with impurities always has BP elevation, MP depression, VP depression. A and D don't make sense, and a "small percentage" isn't numerical, so B.
 
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