January 25, 2021, 02:20:21 PM
Forum Rules: Read This Before Posting


Topic: Why is 1-Decanol not able to hydrogen bond with water?  (Read 12390 times)

0 Members and 1 Guest are viewing this topic.

Offline eglaud

  • Regular Member
  • ***
  • Posts: 53
  • Mole Snacks: +0/-0
Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #15 on: March 08, 2016, 04:28:01 PM »
So is the statement I said originally correct, that hydrogen bonding will occur between molecules that contain an O-H, N-H, or F-H bond? Because if that is true then I guess i'll ignore the other places online who say 1-decanol doesn't form a hydrogen bond with water and say I understand this

Well, yes, but I'd like to see the reference to the online sources that say decanol doesn't hydrogen bond.  Maybe they're simply wrong, but maybe they're explaining something important we all need to understand better.

The first source is from some answers to the lab, they don't list 1-decanol in their answer only in the question. The second source is just yahoo answers

https://quizlet.com/73672416/5-solubility-polarity-electrolytes-and-nonelectrolytes-flash-cards/
https://answers.yahoo.com/question/index?qid=20101011125715AA7B6Q5

Offline eglaud

  • Regular Member
  • ***
  • Posts: 53
  • Mole Snacks: +0/-0
Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #16 on: March 08, 2016, 04:40:24 PM »
On top of this, how does the H-bonds affect solubility? Again, online I see people saying if it can make an H bond it will be soluble in water. My guess is since OH and NH are very polar, it would more or less mean that the molecule will be polar, the exception being the decanol because of all of the carbon atoms. Is this a simple explanation?

Offline eglaud

  • Regular Member
  • ***
  • Posts: 53
  • Mole Snacks: +0/-0
Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #17 on: March 08, 2016, 04:44:25 PM »
Also I find another link saying that the non-polarity will offset the potential hydrogen bonding with 1-decanol.

http://www.answers.com/Q/Can_ethanol_glycerol_sucrose_urea_and_1-decanol_hydrogen_bond_with_water

Offline Arkcon

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 7365
  • Mole Snacks: +533/-147
Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #18 on: March 08, 2016, 06:16:50 PM »
Those are students writing whatever they feel like, without a source. I would stick to your textbook's definition, unless you don't understand it for some reason.

In many ways, those groups are similar to our group here, but we do have a dialog of people addressing each other, that Yahoo Answers lacks.

Can you see from the chart I posted what hydrogen bonding is meant to mean?  Its also visible in the way decanol interacts with itself, giving it a higher boiling point than even longer carbon chains that don't have an OH to hydrogen bond with itself.

Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline Babcock_Hall

  • Chemist
  • Sr. Member
  • *
  • Posts: 4480
  • Mole Snacks: +273/-19
Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #19 on: March 08, 2016, 06:53:42 PM »
On top of this, how does the H-bonds affect solubility? Again, online I see people saying if it can make an H bond it will be soluble in water. My guess is since OH and NH are very polar, it would more or less mean that the molecule will be polar, the exception being the decanol because of all of the carbon atoms. Is this a simple explanation?
The solubility of 1-hexanol in water is 0.6 g hexanol per 100 grams of water.
http://chemed.chem.purdue.edu/genchem/topicreview/bp/2organic/alcohols.html

According to one source, the solubility of hexane in water is 9.5 mg/L at 25 deg C
McAuliffe C; J Phys Chem 70: 1267-75 (1966)
https://pubchem.ncbi.nlm.nih.gov/compound/hexane#section=Melting-Point

What does this suggest about the hydrogen bonding in 1-hexanol?

Offline eglaud

  • Regular Member
  • ***
  • Posts: 53
  • Mole Snacks: +0/-0
Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #20 on: March 08, 2016, 09:05:01 PM »
Those are students writing whatever they feel like, without a source. I would stick to your textbook's definition, unless you don't understand it for some reason.

In many ways, those groups are similar to our group here, but we do have a dialog of people addressing each other, that Yahoo Answers lacks.

Can you see from the chart I posted what hydrogen bonding is meant to mean?  Its also visible in the way decanol interacts with itself, giving it a higher boiling point than even longer carbon chains that don't have an OH to hydrogen bond with itself.

No I don't really see the connection between the chart and hydrogen bonding, sorry.

Offline eglaud

  • Regular Member
  • ***
  • Posts: 53
  • Mole Snacks: +0/-0
Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #21 on: March 08, 2016, 09:08:32 PM »

[/quote]
The solubility of 1-hexanol in water is 0.6 g hexanol per 100 grams of water.
http://chemed.chem.purdue.edu/genchem/topicreview/bp/2organic/alcohols.html

According to one source, the solubility of hexane in water is 9.5 mg/L at 25 deg C
McAuliffe C; J Phys Chem 70: 1267-75 (1966)
https://pubchem.ncbi.nlm.nih.gov/compound/hexane#section=Melting-Point

What does this suggest about the hydrogen bonding in 1-hexanol?
[/quote]

I see that a hydrogen bond encourages solubility here, right?

Offline Babcock_Hall

  • Chemist
  • Sr. Member
  • *
  • Posts: 4480
  • Mole Snacks: +273/-19
Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #22 on: March 08, 2016, 09:27:41 PM »
Yes.

Offline eglaud

  • Regular Member
  • ***
  • Posts: 53
  • Mole Snacks: +0/-0
Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #23 on: March 08, 2016, 09:58:20 PM »
Okay that makes sense, because it'll bond to the hydrogen, essentially dissolving it. What about hexane? I know hexane can't form h-bonds, but it wouldn't discourage it right? Or because they form h-bonds they'll bond to each other and not dissolve as well? Thanks

Offline Arkcon

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 7365
  • Mole Snacks: +533/-147
Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #24 on: March 09, 2016, 06:12:37 AM »
OK.  We're getting closer to some of your points of confusion.

Okay that makes sense, because it'll bond to the hydrogen, essentially dissolving it.

Depends on "it"

Quote
What about hexane? I know hexane can't form h-bonds, but it wouldn't discourage it right?


Oh.  Most definitely not.  Hydrogen bonding occurs between a hydrogen, bonded to to an oxygen, nitrogen, etc and also to another oxygen, nitrogen, etc. There is no hydrogen bonding involved with hydrogens bonded to carbon.

Quote
Or because they form h-bonds they'll bond to each other and not dissolve as well? Thanks

Nope.  Hexane doesn't hydrogen bond with itself. 
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline Enthalpy

  • Chemist
  • Sr. Member
  • *
  • Posts: 3601
  • Mole Snacks: +295/-57
Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #25 on: March 09, 2016, 11:14:44 AM »
It's important to realize that all molecular substances that can be liquid or solid have some forces that bond the molecules together. The hydogen bond is just one of them.

So when water mixes with an other liquid or dissolves a solid, some intermolecular bonds must be broken - some preexist in water, others in the other compound. Sometimes the new bonds are extremely favourable (ammonia, hydrogen chloride...) and the result is clear. Sometimes the change is neutral or slightly unfavourable, but it still happens to a variable amount because heat shuffles the molecules. Sometimes it's so unfavourable that nothing perceivable happens.

So "is there some hydrogen bond" doesn't suffice to answer "do they mix". Mixing water and alcohols of varied carbon backbone length needs to break some existing bonds. Do you see what bonds preexist and how the carbon backbone length influences this?

In a next step, you can imagine heterogeneous "mixes", or better colloids, where only one molecule end "mixes" with water, for instance soaps.

Sponsored Links