Which Boiling Point is Higher: Hex+Prop vs Prop? URGENT!

[KLscilevothma]

Boiling point, urgent !

Which of the following has higher boiling point?
1) Mixture of hexane and propanone
2) propapone
(consider their relative molecular mass and the forces of attraction between the molecules)

I think the mixture of hexane and propanone has a higher boiling point, as propanone has lone pair electrons, therefore the force between the molecules in the mixture is dipole-induced dipole, while the force exists between pure propanone molecules is instantaneous diple-induced dipole.

However my classmate told me the mixture has a lower boiling point and was confirmed by my teacher.

I hope I can get your answer in 3 to 4 hours, if not, it's ok and I'll treat this thread as a discussion. Thanks in advance.

PS. This question is for the theory part of my lab. report. Since the data obtained was ridiculous, that's why I need to know the fact.

PS2. I need to finish it in 4.5 hours.

 

[Viper]

The boiling point of Propane is -42degrees
The boiling point of Hexane is 69 degrees

I think you might be right Mrs Kam

 

[KLscilevothma]

I think you might be right Mrs Kam

Mrs Kam ??! I'm not Mrs Kam.

Propane : C₃H₈
propanone : CH₃C=OCH₃

In fact, i need to draw a graph, variation of boiling point against % composition by volume haxane/propanone mixture. (This is an experiment on phase equilibrium)

 

[HazZy]

acetone

hexane: 68.7
acetone: 56.5

sounds like a boring lab

 

[Bystander]

The word "azeotrope" should appear somewhere in the background material for the lab. Prediction of "azeotropes" is a topic for the M&PS forum.

 

[KLscilevothma]

Originally posted by myself
I think the mixture of hexane and propanone has a higher boiling point, as propanone has lone pair electrons, therefore the force between the molecules in the mixture is dipole-induced dipole, while the force exists between pure propanone molecules is instantaneous diple-induced dipole.

Um..this is wrong. The force between molecules in pure propanone(acetone) is dipole-dipole interaction, since there are 2 lone pair electrons. The bond between molecules in pure hexane is instantaneous dipole-induced dipole. If they are mixed together, hexane molecules will destroy the dipole-dipole interaction between propanone molecules and to form a diple-induced dipole interatction.


Thanks for your help.