Polarity

[Dochopeful13]

Can someone please help with this question.

Place these compounds in order of increasing polarity
CH3F
CH3OH
C6H6
C6H5OH

Am I correct in thinking ch3oh is correct because of the hydrogen bond?

Thanks!

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[MDurgs]

C6H6 < C6H5OH < CH3OH < CH3F

F is more electronegative than O
But you are correct in thinking that C6H5OH < CH3OH because the additional carbon molecules decrease the polarity of the molecule (make it more soluble).

http://chemicalbondinglife.blogspot.com/2013/11/periodic-trends.html

 

[aldol16]

Depends on the question's context and how you're measuring polarity. In terms of dipole moments, CH3F is quite polar - even more polar than CH3OH. But if you need to take into account H-bonding, then CH3OH wins. You're not going to get a question that is a simple ordering of molecules based on polarity - it's always going to be in some broader context. So for instance, it could be asking about elution time off a silica column. In that case, H-bonding would come into play although it's not part of a strict definition of polarity based on molecular dipole.

 

[Dochopeful13]

Depends on the question's context and how you're measuring polarity. In terms of dipole moments, CH3F is quite polar - even more polar than CH3OH. But if you need to take into account H-bonding, then CH3OH wins. You're not going to get a question that is a simple ordering of molecules based on polarity - it's always going to be in some broader context. So for instance, it could be asking about elution time off a silica column. In that case, H-bonding would come into play although it's not part of a strict definition of polarity based on molecular dipole.

Thank you for your help.