Jul 31, 2016
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Rank the following in order of decreasing BP: HF, HI, HBr, HCl

The answer is HF>HI>HBr>HCl, but I'm confused because I was thinking that strong acids would first have higher boiling points than weak acids, then I would rank them according to van der waals after?
 

orgoman22

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Rank the following in order of decreasing BP: HF, HI, HBr, HCl

The answer is HF>HI>HBr>HCl, but I'm confused because I was thinking that strong acids would first have higher boiling points than weak acids, then I would rank them according to van der waals after?
Wow! Where did you ever get such a crazy thought? HF has the highest boiling point because it has hydrogen bonding. The rest of the series goes according to Van Der Waals attractions.

Hope this helps.

Dr. Romano
 

OnlyIfICouldTurnBackTime

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Feb 11, 2015
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BP Trend: Ionic bonds (NaCl, CaSO4, etc) > H-bonds (H-F, H-O(including carboxylic acids' carbonyl O), H-N) > dipole-dipole > London dispersion

More branching in an alkane= less surface area for london dis. force / intermolecular forces to act on = lower BP = higher vapor pressure.

Melting point is another story, more branching there is, higher the melting point for the alkanes. The Destroyer, Bootcamp, chads, and Genius will most definitely guide you through all the trends you need to know (stability, acidity, reactivity, nucleophilicity, etc).
 
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