Questions tagged [hydrogen-bond]

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

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1answer
3k views

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 ...
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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 ...
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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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548 views

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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555 views

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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911 views

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 $274\ \pu K$] $\ce{CH3NH2}$ (...
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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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1answer
549 views

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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449 views

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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587 views

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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Do symmetric hydrogen bonds in neutral molecules exist?

As far as I know, there have only few truly symmetric hydrogen bonds been observed. Unquestionable is the existence of it in the bifluoride ion, $\ce{[F-H-F]-}$, see also here. There are a couple of ...
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Why are trans fats worse than saturated fats?

Saturated fat molecules have no double-bonded carbons, so they are long and straight, which means they stack easier and tend to form solids at room temperature, and solids are better at forming ...
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1answer
295 views

Number of hydrogen bonds of organic compounds?

How to count the organic molecules ' hydrogen bonds in average? What are the numbers of hydrogen bonds formed among alcohols ,alkanoic acids ,aldehyde , ketones , amine ,amide , and ether when they ...
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Tools for investigating hydrogen bonding

What would be the best tool to investigate local molecular organization in liquid mixtures due to hydrogen bonding? For example, I might want to look at how water molecules hydrogen bond to PNIPAM vs ...
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639 views

Hydrogen Bonding (with oxygen) - restricted to oxygen singly bonded to H or not?

I understand the following definition of a hydrogen bond from Merriam Webster: an electrostatic attraction between a hydrogen atom in one polar molecule (as of water) and a small electronegative ...
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How many bonds can Hydrogen make?

Recently I saw a video which told me that Hydrogen has a valency of 1, i.e, Hydrogen can only bond with 1 other atom. But since hydrogen wants a complete shell, it can have 2 covalent bonds with 2 ...
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Does intramolecular hydrogen bonding occur with carbonic acid and geminal diols?

Is an intramolecular hydrogen bond possible in such compounds? What are the requisites to have intramolecular hydrogen bonding?
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How many hydrogen bonds in these compounds?

We usually get some questions about how many hydrogen bonds these compounds can create, we use it to differentiate between the boiling point of each one of them so it would be great if you could help ...
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Would hydrogen bond form in these scenarios?

My notes say that hydrogen bonding occurs between a hydrogen atom covalently bonded to a highly electronegative atom ($\ce{N, O, or F}$) and the lone pair of a highly electronegative atom of another ...
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Can an amide nitrogen be a hydrogen bond acceptor?

Can $\ce{N}$ (i.e. main chain $\ce{NH}$s of recognised residues in a peptide or protein) be a hydrogen bond acceptor? It is a well known fact that the main chain $\ce{NH}$s can be a hydrogen bond ...
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Which are stronger intermolecular forces: ionic bonds or hydrogen bonds? [closed]

Do strong ionically attracted molecules have stronger intermolecular forces than hydrogen bonding forces?
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How polarization effects from cations affect H-bond strength

The average hydrogen-bond strength in pure water is higher than the average H-bond strength between the first and second hydration shells around a $\ce{Al^3+}$ ion (or any cation, for that matter). ...
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It is easier to iron cotton clothes when slightly wet, why?

As the title says, why is it easier to iron cotton clothes when slightly damp ? Has this got something to do with the hydrogen bonding in cotton ?
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Specific Heat Capacity of Heavy Water

Water has an unusually high specific heat capacity due to it's hydrogen bonds. Why is it that the change in isotope causes a 10% difference in the heat capacity? How does the added neutron in the ...
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How does a water molecule bond to an anhydrous salt to form a hydrate?

Some sites suggest that water molecules bong to anhydrous salt via a "loose bond". What does that even mean? $\ce{H2O}$ is a polar molecule and salts are made up of ionic bonds. Is it a hydrogen bond ...
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reference or data on internal hydrogen bond strength

As suggested by the title, I am looking for data on the strength of different internal hydrogen bond configurations. In general, an internal hydrogen bond may form when the donor and acceptor are ...
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1answer
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Dichloromethane solubility in water

I heard dichloromethane is soluble in water 1:50, but I also heard it is not because it can't form hydrogen bonds. I'm confused. Is there a way to extract it? Would putting the water to $40~\mathrm{^\...
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Does alcohol hydrogen in the enol tautomer of a β-dicarbonyl have sp² character?

My reasoning for the somewhat implausible "$\mathrm{sp^2}$" character of the hydrogen between these two oxygens on the enol structure of the right comes from recognizing that if it were, then we would ...
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Is Hydrogen Bonding a Type of Dipole Dipole Interaction?

I understand that dipole dipole forces is due to the attraction of the different partials charges of atoms in different molecules due to their different electro-negativities. For hydrogen bonding, ...
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Why does hydrogen fluoride have a boiling point so much lower than that of water?

$\ce{F}$ has more unshared electron pairs and is very electronegative, so $\ce{H}$ of another $\ce{HF}$ molecule can $\ce{H}$-bond with it. $\ce{HF}$ has normal boiling point of $\pu{19.5^oC}$ while $...
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Hydrogen bonding

It is mentioned in my textbook: "Hydrogen atoms of water molecule create strong electrical field due to their small sizes" How is the size related to electrical field and its strength? A little ...
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Why is the formation of double helix between non complementary sequences disfavoured?

The textbooks starts with the phenomena that double helix is an expression of the rules of chemistry. Hydrogen bonds are important in determining the formation of specific base pairs in the ...
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Physical significance of double-well potential in quantum bonding

I'm currently studying about the hydrogen bond's Potential Energy Surface (PES) pattern. As per literature, single point energy obtained from Density Functional Theory (DFT) using MP2 approximation ...
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Hydration number: Carbonic acid in water

Carbonic acid ($\ce{H2CO3}$) is known to be soluble in water, and that this particular compound is unstable, so much so that according to the 2014 article from Berkeley Lab: New Insights on Carbonic ...
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Electronic density distribution in hydrogen bond

I'm currently studying about the atomic configuration of electrostatic interactions. Concept is there that in case of interactions like in N-H...N-H (amides), the stability depends on the position of ...
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What are the prerequisites in hydrogen bonding?

I know when a hydrogen bond is, but - can hydrogen bonds only occur between two molecules containing hydrogen? Or, only one of the molecules should contain hydrogen and the other one may not contain ...
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Bending of water and methanol towards a charged objects

I just had a question about why does water, methanol or any other polar substances tend to bend towards the charged object. I think it is because of a slight dipole dipole movement between the ...
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Strength of hydrogen bonding in phenol or methanol

I wanted to know whether hydrogen bonding is stronger in phenol or methanol. I saw on Wikipedia about the enthalpies of hydrogen bonding in various cases. but could not find the answer to this ...
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How to simulate surface tension?

I am trying to create a water drop simulation for measuring hydrophobicity of surface. I don't know how to simulate the contact angle which is related by younges equation to the surface tensions for ...
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Why is HCl not considered to have hydrogen bonding?

A molecule that has hydrogen bonding usually follows these two premises. 1.) There is a hydrogen atom involved 2.) Hydrogen must be bonded to a highly electronegative element which are ...