Intermolecular Force Between Alcohols (1 Viewer)

[Web Addict]

Hi.
What is the type of intermolecular force between alcohols? I had this in my chemistry practical test. I put hydrogen bonding, while the rest of my class put dispersion forces. Which is right?
Thank you.

 

[Kurosaki]

I thought dispersion forces are always there in molecules?

 

[2xL]

You are correct.

EDIT: However your class is also correct. Hydrogen bonding accounts for the higher boiling point of alcohols when compared to alkanes but i'm not sure of the context of the question.

 

[someth1ng]

Alcohols experience both dispersion forces from the alkyl chain and hydrogen bonding from the hydroxyl group. I feel that the most correct answer based on what you have said is hydrogen bonding because it constitutes the highly boiling/melting points of alkanols.

 

[Web Addict]

I just found out that the question was in the 2012 HSC Chemistry Exam. It is question 31 if that helps.

 

[someth1ng]

I just found out that the question was in the 2012 HSC Chemistry Exam. It is question 31 if that helps.

The question you posted is NOT the 2012 HSC Chemistry question. The HSC question was a graph of increasing chain lengths of alkanols against melting/boiling point and asked why their boiling points increased as the chain lengthened.

The answer to that one is dispersion forces as all of them contain only one polar group (OH) but the non-polar alkyl chain lengthened and hence, dispersion forces increased.