Questions tagged [hydrogen-bond]

Bond between covalently bound hydrogen atom and atom possessing a lone pair of electrons.

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Which oxygen will form a better hydrogen bond?

Which oxygen will form a stronger hydrogen bond , the one in water or the one in hydrogen peroxide ?? According to me , the one in peroxide will form the stronger H bond as the O here being less ...
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How does hydrogen bonding affect the boiling points of chemical compounds?

My main question is why is the boiling point of methanol so much different from that of water? I understand that both compound are able to develop hydrogen bonding, and obviously water can develop ...
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What is a hydrogen bond acceptor and donor?

I recently read about hydrogen bonding. One thing about which I am really confused is how to distinguish between hydrogen bond acceptors and donors. I looked it up on SE and found this post, which ...
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Steric inhibition of resonance vs. hydrogen bonding

I have to compare the acidic strength of these compounds: Now, in A and B hydrogen bonding will be present which will help stabilize the negative charge of the conjugate base. However, the hydroxyl ...
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Why isn't Indigo soluble in water?

Why isn't Indigo soluble in water? I mean, it has 2 H-N groups, shouldn't it then be able to hydrogen bond with water?
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Common hydrogen bonded liquids [closed]

For some experiments I need liquids with and without hydrogen bond which are pure or highly concentrated. I have only found $\ce{HNO3, CH3COOH}$ concentrated. But i need more liquids. And it would be ...
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Strength of Dipoles, Covalent bonds and H-Bonds

My textbook says: Dipole-dipole forces are 1% as effective as covalent bonds and the strength of a hydrogen bond is generally twenty times less than that of a covalent bond. What do these ...
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How do water molecules overcome the van der waals distance and form hydrogen bonds?

I read in Voet & Voet that the hydrogen bonds are at least 0.5 angstrom shorter than the calculated van der waals distance. As I understand, van der waals distance is the distance of closest ...
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Is there intramolecular hydrogen bonding in salicylaldehyde?

Is there intramolecular hydrogen bonding between the hydroxyl and carbonyl groups? I think personally is that it does but what is concerning me is that I have got no adequate answer or response to my ...
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Why is ice less dense than water?

I know the traditional explanation, which says that ice has large spaces between $\ce{H2O}$ molecules because hydrogen-bonding gives it an open structure. But what does the open structure have to do ...
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Cotton and synthetic clothes [closed]

Why do cotton clothes take a long time to dry as compared to synthetic clothes? I read in a book that cotton fibres form hydrogen bonds with water molecules and thus, the rate of evaporation of water ...
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How do gelatin and aluminium sulfate strengthen paper?

When wet, the hydrogen bonds between the cellulose chains in paper are disrupted due to the formation of hydrogen bonds with water. This leads to the paper becoming extremely weak. This is the case ...
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Boiling points of Butan-2-ol and Butan-1-ol

Butan-1-ol has a boiling point of approx. 117.7 celsius, and Butan-2-ol has a boiling point of approx. 99.5 celsius. What causes this difference in boiling points? My initial idea would be that Butan-...
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Why alcohol is volatile although it has hydrogen bonds?

We are always told that hydrogen bonds increase the boiling point of a liquid and as a result they decrease the liquid's volatility. I want to know the reason why, alcohol with hydrogen bonds is ...
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Hydrogen bonding in concave rings

Can hydrogen bonding occur if both O and H are in a ring having 6 members however the ring is concave . Example 3 hydroxycyclohexanone
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Is there an intramolecular hydrogen bond in guaiacol?

Is there a hydrogen bond between the $\ce{H}$ atom of $\ce{-OH}$ group and the $\ce{O}$ atom of the $\ce{-OCH3}$ group in ortho-methoxyphenol? I was told no. But I want to know why.
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The reason for Hydrogen bonding [duplicate]

Why does hydrogen bonding take place? Is there any kind of electron donation? Or does something like an ionic bond take place?
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Which is more soluble in water, HF or SO2?

I was wondering which is more soluble in water, hydrogen fluoride or sulfur dioxide? Since $\ce{HF}$ will hydrogen bond to other HF particles (as opposed to $\ce{SO2}$ dipole-dipole attraction). ...
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Can chlorine form hydrogen bonds? [duplicate]

My question is simple, If chlorine ($\ce{_17Cl^35^.^5}$) and nitrogen ($\ce{_7N^14}$) have similar values of electronegativity, and chlorine has way more lone pairs than nitrogen, what prevents it ...
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Hydrogen bonds: 1 donor with 2 acceptors at the same time possible (or vice versa)?

Can 1 donor (eg N-H) facilitate 2 H-bonds with 2 different acceptors (eg 2x O) at the same time (assuming that both are within range and angle constraint)? i.e. building an "h-bond triangle"? Is it ...
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How to determine what compounds form hydrogen bonds? [closed]

Which of the following compounds can form hydrogen bonds? a. $\ce{H2S}$ b. $\ce{CH3OCH3}$ c. $\ce{HCl}$ d. $\ce{BH3}$ e. $\ce{NH3}$ Why isn't $\ce{CH3OCH3}$ since $\ce{H}$ is bonded with $\ce{O}$ ...
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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 $\...
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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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salt bridge vs hydrogen bond

I saw this figure on Wikipedia: After seeing this image I got really confused about the difference between these two, or maybe the similarities. Ofcouse I understand that a hydrogen bond can be seen ...
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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 ...