Questions tagged [hydrogen-bond]

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

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Comparing the boiling points of common organic molecules

The order I was provided with is(comparing molecules of similar molecular mass from each); alkanes< ethers< esters< aldehydes< ketones<< alcohols<< carboxylic acids<< ...
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Which of the following compounds possess more than one percent enol content? [closed]

Which of the following compounds possess more than one percent enol content? I understood that stability of enols are dependent on the hydrogen bonding in the compounds. But here, what is the ...
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What happens when hydrogen bonds stretch?

I'm researching about the Mpemba effect and I came across an explanation saying that the effect occurs because at higher temperatures, the hydrogen bonds between the water molecules stretch and store ...
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Hydrogen bond in aqueous solutions

Is hydrogen bond the attraction between a hydrogen atom bonded to a highly electronegative atom (N, O, F) and a lone pair? If this is true, in aqueous solutions, are there always hydrogen bonds ...
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How do point mutations affect complementary base-pairing and widths of the nucleotide pairs?

Point mutations are divided into two categories: transitions and transversions. Since point mutations only occur during DNA replication (an integral process of both mitosis and meiosis), the mutated ...
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How to interpret this formula about hydrogen bond energy

I want to evaluate some chemistry related formulas, which I don't understand. In proteins, hydrogen bonding often occurs between the oxo group = O oxygen of one amino acid and the α-amino group (N − H)...
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Why are Hydrogen bonds directional? [duplicate]

While reading about Hydrogen bonding in a book (O.P. Tandon's G.R.B. Organic Chemistry), I came across a sentence that was mentioned in a rather unstructured way relative to how comprehensive I was ...
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97 views

Why is boiling point of Ammonia greater than Arsine?

I have previously read that the boiling point of Stibane(SbH3) is greater than Ammonia(NH3) as ammonia is gas at room temperature and no hydrogen bonding exists in the gaseous form of NH3. Hence, as ...
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Is “Hydrogen Bonding” coordinate covalent bond? [closed]

My textbook says: The Oxygen atom of other molecules links to form coordinate covalent bond with H-atom using lone pair. Now I am confused. Is H-bonding coordinate covalent bond?
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How is o-Fluorophenol more acidic than phenol even after having Hydrogen bonding?

Source: Concepts of Organic Chemistry by Dr OP Tandon, Himanshu Pandey, Dr AK Virmani Page no: 241
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Why does hydrogen bonding require a lone pair? [closed]

Why does hydrogen bonding require a lone pair of electrons on the partially negative atom? They would still be partially negative even without the lone pair right? Or does a bond exist, but is much ...
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Why ethyl cyanide and propanol have the same boiling point?

As I understand, the intermolecular forces of ethyl cyanide are of van der Waals nature (dipole-dipole) but in the propanol molecule there are hydrogen bonds which are in principle much stronger. Why ...
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Hydrogen bonding in acetylene and other terminal alkynes

My textbook says that hydrogen bonding is possible only when there is acidic hydrogen connected to an electronegative atom like $\ce{N}$, $\ce{O}$ or $\ce{F}$ and a basic lone pair of electrons on ...
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Why is Bonding between H and Cl not considered as H bonding? [duplicate]

Cl is an electronegative element and hydrogen is electropositive. Why are intermolecular interactions involving H and Cl not considered as H bonding? I read it in a book but there was no reason given ...
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Effect of isotopes on H-Bonding

The following question was asked in one of the assignments my teacher has given. Acetone ($\ce{Me2CO^16}$) on treatment with $\ce{H2O^18}$ gives a mixture of $\ce{Me2CO^16}$ and $\ce{Me2CO^18}$, the ...
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Compare the boiling points of isobutane and 1-butyne

Question: Compare between the boiling points of isobutane and 1-butyne The answer to this question is given as 1-butyne has higher boiling point than isobutane. My approach: I have been taught a few ...
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550 views

Relative strength of intermolecular forces [duplicate]

My attempt at a solution: First I look for hydrogen bonds: The only compounds with hydrogen bonds are the second and fourth ones, so they have the strongest intermolecular forces. The second must have ...
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Hydrogen bonding in sugar acids

I recently learnt that the reason for low solubility of mucic acid as compared to glucaric acid was more hydrogen bonding in the crystal state of mucic acid as compared to glucaric acid. I would ...
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Why isn't there a hydrogen bond present between the oxygen atom and hydrogen atom of adjacent alcohol groups?

*I know that there is inter-molecular hydrogen bonding between the molecules of glycerol. *What makes the adjacent alcohol groups behave differently towards each other as compared to when they ...
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57 views

Why don't dicarboxylic acids show hydrogen bonding in spite of the fact that carboxylic acids exist usually as dimers in polar aprotic solvent? [closed]

I have seen several examples: The fact that maleic acid is more soluble in water than fumaric acid in spite of the fact that it must be able to show intramolecular hydrogen bonding. trans-...
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139 views

What is exposed in the surface tension of water?

(I guess) I understand the covalent bonding of water and the hydrogen bonding of water between two different molecules, but I would like to know which part is the part that that exposes itself to the ...
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Why aren't the hydrogen bonds in carboxyllic acids like this?

Why don't carboxylic acids form H-bonds in this formation with the red dots (diagonal) instead of the black dots (horizontal)? I was always taught that H-bonds formed between partially negative and ...
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Water solubility comparison of stereoisomers of bicyclo [4.4.0] decane-3,4-diol

I think, (I) must be more soluble in water. It is due to trans configuration and thus, forming more effectively inter-molecular hydrogen bonds with water molecules.
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Factors dominating forces between acetone and chloroform

What type of interaction is present between acetone and chloroform? According to me, acetone has weak hydrogen-bonds with chloroform, the hydrogen on an electronegative atom has electron density that ...
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Solubility of ortho- and para-nitrophenol in benzene

Which one between o-nitrophenol and p-nitrophenol is more soluble in benzene? And what is the reason? If the solvent had been polar, hydrogen bonding would have provided a lot of explanation, but what ...
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If acid releases proton then how can a proton react with another proton to form hydrogen gas? [duplicate]

As we know that acid releases proton (H+ ion) when dipped in water hydrogen has a proton and electron only . To form H+ hydrogen releases 1 electron and it becomes proton. But when Acid reacts with ...
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How does the entropic force arise within the hydrophobic effect?

I know that the hydrophobic effect is usually explained by the entropic effect originating from the disruption of hydrogen bonds between molecules of water and the nonpolar substance. The hydrogen ...
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How to get the right formulas for combustion (rocket chamber) or where to find them? [closed]

I am a space enthusiast and am intrigued mostly by rockets. I recently found a book HOW to DESIGN, BUILD and TEST SMALL LIQUID-FUEL ROCKET ENGINES and have been fiddling around with rocket engine ...
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How the attraction takes place between a hydrogen atom and the acceptor atom in a hydrogen bond

In hydrogen bonds present in water,does the hydrogen atom attracts to the lone pair of electrons present on the oxygen atom or to its partial negative charge? If former is the case are there any ...
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492 views

Do amines or alcohols have stronger intermolecular hydrogen bonds?

Which has stronger hydrogen bonding, $\ce{CH3OH}$ or $\ce{CH3NH2}$ I think it comes down to which has more dominance; number of hydrogens, number of lone pairs, or electronegativity.
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Extent of Hydrogen bonding in H2O2

Several books that I have read say that in $\ce{H2O2}$ the degree or extent of H-bonding is 6 as each H atom would form 1 and O atom would form 2 H-bonds respectively. However if we look at HF the no....
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it is possible for the hydrogen bond to form between the hydrogen chloride molecule, HCl? [duplicate]

Recently I'm doing my work, and I can't find what it is the answer. Can you guys help me?
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Is a compound that reacts with another to form hydrogen for fueling aircraft possible [closed]

Hydrogen is the most abundant element in the universe and has great properties when reacting with oxygen for use as a fuel. Yet here on Earth, its production is prohibitively expensive, its storage ...
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Why do boiling points of alkanes and alcohols become closer with increased chain length

I came across this graph, which clearly shows a large difference between the boiling points of alkanes and their equivalent alcohols. However, it is clear that as chain length increases, the ...
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Effect of intramolecular hydrogen bonding on the stability of a molecule

What will be the effects of intramolecular hydrogen bonding on the stability of a molecule? Will it increase or decrease the overall stability of a molecule? Or will it not have any impact on the ...
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Strength of Hydrogen Bond and Angle

This link has a short paragraph on the very first page, which says: "There are two useful criteria to evaluate the presence and the strength of a H-bond. The first is to look at the distance between ...
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which oxygen atom make intramolecular hydrogen bond in salicyclic acid?

When I googled about intramolecular hydrogen bonding in Salicylic acid, I found that there are two type of hydrogen bonding. Which one is more appropriate? And another question, if there ARE two ...
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Why does Pubchem show cis-1,3-cyclohexanediol with the hydroxyls in the equatorial position?

I am a beginning organic chemistry student and trying to reason about something based on information in my book, but seeing that Pubchem gives a different structure than I'd expect. In considering a ...
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Hydrogen Bonding by Carbenes

A hydrogen bond is formed between hydrogen attached to highly electronegative atoms (nitrogen, oxygen, and fluorine) which are small in size too and the non-bonding pair of electrons of another such ...
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Increase of peak intensity in case of hydrogen bonding

Typical motif in case of hydrogen bonds is charge transfer from electron rich acceptor Y to (usually) anti-bonding X-H σ* orbital. If so, the X-H bonding distance increases, bond weakens, stretching ...
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Why does ammonia have higher melting point but lower boiling point than HF? [duplicate]

I guess the reason is hydrogen bonding, but shouldn't both the trends be similar in that case?
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Hydrogen bonding of chlorine [duplicate]

Even though nitrogen is less electronegative than chlorine according to Pauling scale bit why don't it form hydrogen bonding as effective as of nitrogen ? ( Electronegativity valve of N =3.0,Cl=3.2)
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Why mixing water with ethanol produces heat energy? [closed]

Sorry if I'm asking something stupid but I'm trying to understand where this energy gets from. As far as I could find, it is not a reaction as both chemicals left unchanged, so it might have something ...
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Why does energy need to be “compensated” in order for solvation to occur?

I am currently learning about the physical properties of alcohols. I understand that the main intermolecular forces between alcohols and water are hydrogen bonds. When these two are mixed, the ...
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Boiling point of ethanamide vs propanamide

I just have a question regarding the boiling points of some primary amides. Ethanamide has a boiling point of 222 °C, while propanamide has a lower boiling point of 213 °C. Both amides are capable of ...
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Why is dichloromethane immiscible in water?

We know that like dissolves like. And dichloromethane is a polar solvent and water is also a polar solvent. Also there ought to be a strong hydrogen bonding between the chlorine and hydrogen atoms. So ...
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Diazo Coupling reaction with para-substituted phenol?

Usually Diazo coupling occurs at para-position unless the para-position is occupied, in which case coupling occurs at ortho-position. While solving questions I found in both the cases as shown, the ...
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Does increasing # of hydrogen bonds decrease the strength of these bonds?

I saw the question, "Is the strength of hydrogen bonding greater in hydrogen peroxide or water?" and it made me think of a question on hydrogen bonding: If an oxygen on a water has a ...
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Hydrogen Bonding in Water (MO theory)

Valence Bond Theory tells us that each of the “sp3” (in reality, 44% s character) oxygen line pairs in water can act as electron donors, but observing the MO diagram for water tells us that the 2 non-...
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Complementary base pairing

In the molecular structure of a DNA it is seen that purines (adenine and guanine) bind with pyrimidines (cytosine, uracil and thymine) through hydrogen bonds, and this is always between a purine and a ...

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