Questions tagged [hydrogen-bond]
Intermolecular force between covalently bound hydrogen atom and atom possessing a lone pair of electrons.
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Identifying functional groups with labile hydrogens from IR hydrogen bonding region [closed]
Here is the $\pu{2000-4000 cm^{-1}}$ spectral region (known for showing hydrogen bonding interactions, $\ce{-H\bond{<-}X-}$) for three different compounds, each showing a different functional group:...
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Hydrogen Bonding in Water Phase Changes
How is the disparity between the heat of fusion and the heat of vaporization for $\ce{H2O}$ best explained?
A) It takes more hydrogen bonds for water to fuse than it does to vaporize.
B) Water ...
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Why does the distance between atoms in a hydrogen bond impact the strength of the bond?
Wouldn't the distance be irrelevant as after they are attracted they will just close the gap? E.g. once 2 magnets are close enough to be attracted, isn't the distance irrelevant to the strength of the ...
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Can 1 gram hyaluronic acid really hold 6L of water?
According to this study (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3970829/), they make an (uncited) claim about hyaluronic acid: "One of its most important properties is that it can attach and ...
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Distinguishing atom types
How does one recognize lipophilic points, hydrogen bond acceptors and hydrogen bond donors in organic molecules? For example, provided this SMILES instance
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IChO problem involving the condensation point of NF3, NHF2, NH2F
This is a problem from the 2016 International Chemistry Olympiad (IChO):
Which of $\ce{NF3}$, $\ce{NHF2}$, and $\ce{NH2F}$ condenses at the lowest temperature?
The answer book says that it is $\ce{...
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Intermolecular forces between carbon dioxide and water
I'm wondering which intermolecular forces will exist between carbon dioxide and water. Instinctively, I would expect there to be only dispersion forces between the 2 molecules, because carbon dioxide ...
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Does fumaric acid form stronger hydrogen bonds than maleic acid?
My book claims:
Fumaric acid can form intermolecular hydrogen bonds (strong) while maleic acid forms intramolecular hydrogen bonds (weak), hence fumaric acid has higher boiling point than maleic ...
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Relative strengths of hydrogen bonds
Order of hydrogen bond strength:
$\ce{O-H...N}$ > $\ce{O-H...O}$ > $\ce{N-H...N}$ > $\ce{N-H...O}$. Why is that so?
According to me $\ce{O-H...O}$ should have the maximum strength while $\ce{...
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Molecules having higher enthalpy of vaporization and boiling point than another but with lower entropy of vaporization?
I came across the Trouton's rule that predicts the entropy of vaporization of most molecules to be around 85~88kJ/(K mol). It is said to fail when there is hydrogen bond between molecules.
When I ...
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Hydrogen Bond Without Hydrogen
Surely, by the same logic, any atom with a moderate electronegativity (carbon, phosphorus, silicon) can form a polarise covalent bond with an atom with a high electronegativity (fluorine, oxygen). ...
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What Is A Hydrogen Bond? [duplicate]
I know this might be a bit of a silly question, but what is a hydrogen bond? I always thought that (say in water for example) the hydrogen was slightly more negative than the other ion (oxygen). But ...
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Organic problem: acidity of benzene substituents
Ortho nitro benzoic acid is more acidic than para benzoic acid since intermolecular H bonding comes into play in the latter compound. But why is that among para nitro phenol and ortho nitro phenol, ...
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Hydrogen bonding in solid bicarbonates
Why is there two different kinds of hydrogen bonding in solid bicarbonates $\ce{NaHCO3}$ and $\ce{KHCO3}$? In both cases we consider anions of each for hydrogen bonding .
The anions involved in ...
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Hydrogen bond of ozone [duplicate]
Why can't $\ce{O3}$ form hydrogen bonds with water? It has lone pairs of electrons. I do not know the answer.
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Structure of the bifluoride anion [duplicate]
I came across this structure of $\ce{HF2-}$ and realized that the bond shown between H and F is a hydrogen bond.
$$\Large\ce{[F-H-F]-}$$
HF hydrogen bond are the strongest hydrogen bonds we know, ...
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Why is the boiling point of stibane higher than that of ammonia?
I recently came across the fact that the boiling point of $\ce{SbH3}$ (stibane) is greater than that of $\ce{NH3}$ (ammonia). I was expecting $\ce{NH3}$ to have a greater boiling point as a ...
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Does oxygen gas form hydrogen bonds?
I learned that hydrogen bonding is formed from a 'sandwich' of hydrogen and either oxygen, nitrogen, or fluorine where nitrogen, fluorine, or oxygen is the bread.
Will oxygen gas and water form ...
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Are hydrogen bonds stronger than ionic bonds? [closed]
What is the order of strongest bonds to weakest? Are hydrogen bonds stronger than ionic bonds? Are hydrogen bonds covalent bonds?
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Why do Asn-Ser and Gln-Thr have different H bonding patterns?
I noticed that Asn-Ser H-bonding is different from the H-bonding between Gln-Thr.
However both have the same functional groups. I wasn't able to find any information about this. Maybe it's due to ...
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Why do amino acids hydrogen bond rather than ionic bond when they are forming secondary structures in proteins?
When peptide bonds are formed between amino acids, electron delocalisation causes the N to be more positive and the O to be more negative. As a result, why does 'hydrogen bonding' occur to form ...
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Why can't chlorine atoms form hydrogen bonds? [duplicate]
Why can't chlorine atoms form hydrogen bonds even though they have very similar electronegativity to nitrogen, which can?
Electronegativities are as follows:
$\ce{Cl} - 3.16$
$\ce{N} - 3.04$
Is it ...
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Why can't alcohols form hydrogen-bonded dimers like carboxylic acids?
Carboxylic acids such as acetic acid are capable of forming dimers:
I'm wondering why alcohols like ethanol don't generally form dimers. In the diagram below, the oxygen atom on the left ethanol ...
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Hydrogen bonding in alcohols vs amines
Consider an alcohol and an amine compound with roughly the same molar mass. If I understand correctly, the boiling point for the alcohol is greater for two reasons:
The $\ce{O-H}$ bond is more polar ...
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Why there is hydrogen bonding involved in salt bridge formation between glutamic acid and lysine?
I saw this figure on Wikipedia:
After seeing this image I got really confused about the difference between these two, or maybe the similarities. Of course, I understand that a hydrogen bond can be ...
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Water and Ice - density
We know that ice has a lower density than water despite both having the same [molecular] mass. I know that as water turns to ice, it expands. As far as I was taught, I know that it has something to do ...
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Why is the boiling point of water and ammonia so different?
Boiling point of water is 100 degrees Celsius, while boiling point of ammonia is minus 33 degrees Celsius, which makes 133 degrees difference. Now when we discuss value of boiling point, we also say ...
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Water hydrogen bond [duplicate]
In my book it states each water molecule can hydrogen bond to 4 other water molecules. However, it does not state why this is? Why is it 4 molecules and not 3? Is this related to the electron ...
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Why is DMSO more polar than other solvents, yet it dissolves ionic compounds worse?
I'm working right now in the solvent importance in ionic character, and I noticed how a binary salt ($\ce{CuCl2}$) dissolved better in methanol than in dimethylsulfoxide, and in contrast, a ...
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Can glutamic acid and arginine form H-bond at physiological pH?
I was wondering if, say, glutamic acid and arginine can form H-bonds at physiological pH?
According to the figure arginine has a $\ce{NH3+}$ group and glutamic acid a $\ce{COO-}$ group at ...
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Explain volume contraction in mixtures of alcohol and water
Could someone explain why volume contraction occurs when you mix an alcohol such as ethanol with water in relation hydrogen bonding and the dipole-dipole forces?
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Hydrogen bonding relating to molecular orbital theory
In [1, p. 232] here is an explanation of how alcohols hydrogen bond to each other and I do understand how the alcohols form hydrogen bonds to each other:
FIGURE 6.15 Water and alcohols are both ...
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Which dicarboxylic acid has the most acidic hydrogen?
Which of the following acids (maleic, fumaric, succinic, or malonic) has the most acidic hydrogen?
I think that malonic acid should have the most acidic hydrogen due to the presence of an active ...
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Which base pair is more stable, U:G or I:C?
As a result of damage (usually deamination), DNA will sometimes contain uracil and inosine bases. I am trying to determine which unnatural base pairing combo would be more stable: uracil paired with ...
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Energy of hydrogen bonds vs. kinetic energy of water molecules
I watched an extremely engaging video "Why does ice float in water?" by George Zaidan and Charles Morton, https://www.youtube.com/watch?v=UukRgqzk-KE. In particular, video says "Below 4oC kinetic ...
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Why acetaldehyde and acetone have almost equal water solubility? [closed]
Given that boiling point of acetaldehyde and acetone are different due to H-bonding, why doesn't H-bond affect the solubility of these compounds in water?
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Which isomers (cis or trans) are more water soluble?
As a general sense I know that cis isomers are less symmetrical and more polar in nature whereas trans isomers are less polar. Now given those information, would it be appropriate to assume that cis ...
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Are there any other elements that get less dense in their solid state?
I was learning about how water, because of its hydrogen bonds, actually gets less dense as it goes into its solid state - I was just wondering, what other elements do this? Are they similar to water?
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Does clay absorb water because of polarity?
From what I have recently learned about ceramics, clay is essentially sheets of silicon and oxygen, bonded by covalent bonds. Between them, water keeps clay from forming a full lattice of $\ce{SiO4^{2-...
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Does hydrogen bonding contribute in solubility of a substance
If a compound can't hydrogen bond with itself but can hydrogen bond with the water, why does it still remain immiscible?
Take for example ethoxyethane. It can't hydrogen bond with itself but its ...
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What is a hydrogen bond?
I was doing a little research on the Chemistry of water, and it said that water molecules have a hydrogen bond between them. What is it, and what does it do to water?
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Model of London forces and Hydrogen Bonding; the question is carried on forward, partially, as a personal question, from another question [closed]
Does Model of London forces and Hydrogen Bonding are themselves complicated and require multiple sub-models and assisted theories to explain its correctness.
I asked this question in the form (...
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How to determine what organic molecule has the highest boiling point?
Compare and answer which one has the highest boiling point:
$\ce{CH3CH2CH2CH3}$ (butane) ... [$\pu{−1}$ to $\pu{1^\circ C};\ 30$ to $\pu{34^\circ F};\ 272$ to $274\ \pu K$]
$\ce{CH3NH2}$ (methylamine)...
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Comparing strengths of Hydrogen Bonds
What kind of a bond is the Hydrogen bond? Is it electrostatic forces of attraction or more like a partial coordinate bond?
What pair of atoms would provide us the strongest Hydrogen bond? If we ...
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Volume changes when mixing DMSO and water
Since I know that a mixture of 500ml $\ce{H_2O}$ and 500ml ethanol gives less than a liter of mixture I wonder how strong this effect is when mixing DMSO and $\ce{H_2O}$. I'd assume it's nonzero - but ...
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Hydrogen bonding in complex compounds?
Does the water molecules in coordinated water (where water acts as ligand) form hydrogen bonding with other complex molecules? Will the water molecules inside the complex form intramolecular hydrogen ...
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Why are amines more soluble than ethers in water?
For example, diethyl ether ($\ce{C2H5OC2H5}$) has a limited solubility of $6.05\rm~\frac{g}{100~mL}$ water at $25\rm~^\circ C$. However, diethylamine ($\ce{(C2H5)2NH}$) is a lot more soluble in water. ...
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Hydrogen donor without hydrogen acceptor?
Is there a molecule that can donate a hydrogen to a hydrogen bond but not accept one? It would seem that since the donated hydrogen needs to be bonded to an electronegative atom, that electronegative ...
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Hydrogen bonding in staggered vs eclipsed conformations
In my first semester of organic chemistry, we learned that staggered conformations have lower energy/higher stability.
However, my thought is that if you have interacting OH groups, the hydrogen ...
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Why is the boiling point of sulfuric acid much higher than that of phosphoric acid?
Why is boiling point of sulfuric acid much higher than that of phosphoric acid?
According to the data book,
• The boiling point of sulfuric acid is 337 °C (639 °F; 610
K) When sulfuric acid is ...
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