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Topic: Why is 1-Decanol not able to hydrogen bond with water?  (Read 12401 times)

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Offline eglaud

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Why is 1-Decanol not able to hydrogen bond with water?
« on: March 06, 2016, 03:50:09 PM »
1-decanol has an O-H bond, which in my book says is what decides if something can form a hydrogen bond. But I've read that 1-decanol does not form a hydrogen bond with water- why is this?

Offline Arkcon

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Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #1 on: March 06, 2016, 04:36:02 PM »
Theoretically, an electronegative atom like nitrogen or oxygen does hydrogen bond with water. In practice, how do you know decanol is or isn't contributing to hydrogen bonding?
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline eglaud

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Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #2 on: March 06, 2016, 04:46:25 PM »
I'm not sure, in this lab we found that it is non-polar, does that have anything to do with it? Like I said I thought it would form these bonds, I'm not sure why it wouldn't

Offline Enthalpy

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Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #3 on: March 06, 2016, 06:01:31 PM »
I too expect 1-decanol to enable a hydrogen bond with water. But would this imply that they mix?

1-decanol has a permittivity of 8.1, compared with 2.0 for decane. "Polar" may be a matter of definition, then: how much polar, and enough for your definition or not.

Offline Vidya

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Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #4 on: March 06, 2016, 06:21:08 PM »
1-decanol has an O-H bond, which in my book says is what decides if something can form a hydrogen bond. But I've read that 1-decanol does not form a hydrogen bond with water- why is this?
Alcohols have polar(O-H) bond and non -polar hydrocarbon ...compare the amount of non polar part with polar part ...

Offline Arkcon

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Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #5 on: March 06, 2016, 06:40:50 PM »
I'm not sure, in this lab we found that it is non-polar, does that have anything to do with it? Like I said I thought it would form these bonds, I'm not sure why it wouldn't

This explanation of yours, in some ways is desperately missing a point, as the others have pointed out.

I know 1-decanol isn't water soluble.

And you say somehow that means it doesn't hydrogen bond.

Lookup the definition of hydrogen bonding.  What does it mean for a molecule.  You won't find water solubility as a property.
« Last Edit: March 06, 2016, 08:51:42 PM by Arkcon »
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline eglaud

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Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #6 on: March 06, 2016, 07:29:11 PM »
I'm sorry I really don't understand the points you're making. All I've done is ask questions and yet you say that I've been making these claims that insoluble in water = doesn't hydrogen bond, but all I've said is that this is non-polar (in regard to what we've been taught is non-polar).

But regardless, clearly my knowledge on this subject is lacking, so could you explain why my book says that it will form a hydrogen bond when it doesn't? I just don't understand this subject.

Offline Vidya

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Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #7 on: March 06, 2016, 07:43:28 PM »
Ok let me help you ...if you check the solubility of alcohol family in water....lower members are highly soluble like CH3OH or C2H5OH ...however as you increase the hydrocarbon part which is non polar or hydrophobic solubility decreases for example C7H15OH or C10H21OH(decanol) though they can form hydrogen bonds with water due to OH part in the molecule but C10H15 --- is very big non polar part so it makes it insoluble in water.

Offline Arkcon

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Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #8 on: March 06, 2016, 08:49:29 PM »
But regardless, clearly my knowledge on this subject is lacking, so could you explain why my book says that it will form a hydrogen bond when it doesn't? I just don't understand this subject.

Because it does form hydrogen bonds.  With itself, and likely with water too.  That's what "forms hydrogen bonds" means.  I don't know why you said it at the beginning of the thread, and why you keep saying it when we correct you.

Look at the properties of water, which hydrogen bonds,compared to other elements which don't.And compare the boiling point of 1-decanol, and decane,and longer hydrocarbons.

[EDIT]

Like you've said, decanol is non-polar.  But what does that have to do with hydrogen bonding, by any definition?
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline Burner

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Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #9 on: March 06, 2016, 09:55:41 PM »
I'm sorry I really don't understand the points you're making. All I've done is ask questions and yet you say that I've been making these claims that insoluble in water = doesn't hydrogen bond, but all I've said is that this is non-polar (in regard to what we've been taught is non-polar).

But regardless, clearly my knowledge on this subject is lacking, so could you explain why my book says that it will form a hydrogen bond when it doesn't? I just don't understand this subject.

1. Be aware that a molecule can form hydrogen bond with water without being able to dissolve in water.
2. From wikipedia:
Quote
A hydrogen bond is the electrostatic attraction between polar groups that occurs when a hydrogen (H) atom bound to a highly electronegative atom such as nitrogen (N), oxygen (O) or fluorine (F) experiences attraction to some other nearby highly electronegative atom.
That should give you some more clues.
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If I make any mistakes in the forum, please don't hesitate to correct me as I want to learn.

Offline Enthalpy

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Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #10 on: March 07, 2016, 07:38:43 AM »
[...] solubility of alcohol family in water... lower members are highly soluble like CH3OH or C2H5OH [...]
Soluble or miscible?

Online Babcock_Hall

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Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #11 on: March 07, 2016, 09:38:41 AM »
This thread illustrates some of the problems one encounters in teaching about polarity.

@OP, Water and diethyl ether are immiscible.  However, water is more soluble in diethyl ether than it is in hexane.  Why?

Offline eglaud

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Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #12 on: March 07, 2016, 08:16:53 PM »
But regardless, clearly my knowledge on this subject is lacking, so could you explain why my book says that it will form a hydrogen bond when it doesn't? I just don't understand this subject.

Because it does form hydrogen bonds.  With itself, and likely with water too.  That's what "forms hydrogen bonds" means.  I don't know why you said it at the beginning of the thread, and why you keep saying it when we correct you.

Look at the properties of water, which hydrogen bonds,compared to other elements which don't.And compare the boiling point of 1-decanol, and decane,and longer hydrocarbons.

[EDIT]

Like you've said, decanol is non-polar.  But what does that have to do with hydrogen bonding, by any definition?

I am not saying being polar has anything to do with hydrogen bonds, I asked if it did but now I know that it does not. I wondered if it did because our current knowledge about this molecule is that it is nonpolar, so I wondered if there was a connection that's all. I keep saying it because other online sources disagree with that statement, that it does not form with hydrogen bonds with water. I still am confused about all this, so if two substances form hydrogen bonds then they can form one between each other?

If it changes anything, in our lab we found if these things were soluble w/ water and hexane, and conductive. The question asks "which of the following are able to hydrogen bond with water: ...1-decanol... Identify the structural feature which allows for its ability to hydrogen bond. Explain how H-bonding influences the solubility of each in water and hexane."

I'm not looking for an answer to copy, I want to understand why. 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

Offline Arkcon

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Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #13 on: March 07, 2016, 08:36:06 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.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Online Babcock_Hall

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Re: Why is 1-Decanol not able to hydrogen bond with water?
« Reply #14 on: March 08, 2016, 09:36:10 AM »

I am not saying being polar has anything to do with hydrogen bonds, I asked if it did but now I know that it does not. I wondered if it did because our current knowledge about this molecule is that it is nonpolar, so I wondered if there was a connection that's all. I keep saying it because other online sources disagree with that statement, that it does not form with hydrogen bonds with water. I still am confused about all this, so if two substances form hydrogen bonds then they can form one between each other?

Polarity is a complex idea, and being able to form H-bonds does make a compound more polar, all else held equal.  1-decanol is both a hydrogen bond acceptor and a hydrogen bond donor.  However in the case of 1-decanol, the large size of the nonpolar portion of the molecule has to be factored into the molecule's overall polarity.

Why is water more soluble in diethyl ether than it is in hexane?

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