Questions tagged [hydrogen]

Questions regarding the chemical properties of hydrogen and its behavior in reactions and compounds.

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48 views

H and H- atomic and ionic radius

A hydrogen anion has a bigger radius than neutral H . Why is this happening ? I mean both electrons exist at the same shell so this is not it. Both H- and H have 1 proton so this is not it as well . ...
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296 views

Mechanism for interconversion of spin isomers of hydrogen

What is the mechanism by which the ortho- and para- spin isomers of hydrogen interconvert? If such a mechanism exists, does this mean that ortho-hydrogen increases in concentration on increasing ...
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Why are hydrogenation reactions exothermic?

I learned that all reactions that yield hydrogen are endothermic (such has reforming) and reactions that use up hydrogen are exothermic (FCC cracking, hydrogenation, etc.). But why is this so? I know ...
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Acidity of ethanal vs propyne

I want to compare the acidities of 1)terminal hydrogen of propyne 2)hydrogen bonded to the sp3 carbon in propyne 3)alpha hydrogen of ethanal. My idea is that the terminal hydrogen of propyne is ...
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Why is triatomic hydrogen relatively short-lasting?

The first chapter of Fleming's "Molecular Orbitals and Organic Interactions," describes the formation of triatomic hydrogen. In summary, the sigma MO of diatomic hydrogen interacts in phase with the ...
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2answers
383 views

Can gaseous hydrogen and gaseous oxygen be compressed without reaction?

I'm looking into building a clean Bunsen-style burner (or rocket engine - I haven't decided yet). I will be using electrolysis to extract hydrogen and oxygen from water, but the apparatus I am ...
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3answers
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Difference between Lindlar and Rosenmund catalysts

Is there any difference between the Lindlar and Rosenmund catalysts? I've checked around, and it seems the same compounds are used to make both. Is there a difference in their reactivities or are they ...
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1answer
71 views

Most dense hydrogen containing composition [closed]

I am searching for a composition which could host the most hydrogen atoms in a specific volume. Note that this density is sought for justifiable conditions in terms of pressure, temperature, ... and ...
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1answer
52 views

How can I neutralise H2 gas without burning it? [closed]

I was thinking of maybe making it bubble into a solution containing something that would react with H2 yielding either a dissolved substance or a precipitate from the reaction. Maybe a solution with ...
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4answers
3k views

Lifetime of a (reversible) hydrogen fuel cell system

I am trying to determine how long a system that constantly converts water into H and O and then back will last, as in roughly how many cycles. Now this system can either be made of say a reversible ...
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55 views

Why does hydrogen burn spontaneously in fuel cell at room temperature?

It's well known that if you mix $\ce{H2}$ and $\ce{O2}$ in ambient conditions, the $\ce{H2}$ will be stable indefinitely, and will only react with $\ce{O2}$ to form water when ignited by a flame. The ...
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Reaction mechanism of combustion of hydrogen

After a discussion about the usefulness of hydrogen fuel for cars with a friend of mine, I wondered what the reaction mechanism for combustion of $\ce{H2}$ was. I only study (well almost) organic ...
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168 views

Gas chromatography flame ionization detector (FID) - why hydrogen gas?

Why is $\ce{H2}$ used in an FID, apart from the fact its combustion does not contaminate the flame? In other words, is the temperature of the flame important or critical? Is the stability of the ...
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Is a hydrogen molecule smaller than hydrogen atom?

Recently I came across a textbook of physical chemistry which stated the following: In the formation of a stable hydrogen molecule, two hydrogen atoms share a pair of electrons between them and two ...
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Ordering the lines obtained in the H line spectrum based on energy they possess

I am trying to do the following question which asks me to calculate the wavelength of the green line in the visible spectrum of H. The authors claim that the green line is the second most energetic ...
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Inorganic reactions related to nascent hydrogen [closed]

Nascent hydrogen is prepared by (A) $\ce{Na}$ and $\ce{C2H5OH}$ (B) $\ce{Al}$ and $\ce{NaOH}$ (C) $\ce{Zn}$ and dil. $\ce{H2SO4}$ (D) All of these My attempt I know that option (A) &...
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On the stability of deuterium

The isotope of hydrogen, tritium, is indeed radioactive resulting in $\ce{^3He}$ through beta decay. But what of the radioactively 'stable' isotope deuterium? Are all deuterium atoms destined to be ...
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1answer
77 views

Home-grown diamond using CVD

I want to make a diamond at home using chemical vapor deposition (CVD). If I use a metal chamber filled with methane and hydrogen gas and heated with a microwave oven oscillator element, will the ...
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6answers
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Why do we use helium in balloons?

While I was looking at the periodic table today, I realised that there were gases that were much lighter than helium such as hydrogen. If hydrogen is lighter than helium, why do we insist on using ...
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59 views

Converting hydrogen to methane

I am in need of small amount of pure methane for laboratory purpose. I have hydrogen generator in the lab. Is there a possibility of generating methane from hydrogen ? May be make hydrogen flow ...
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1answer
62 views

Standard litres to kg conversion for Hydrogen [closed]

When looking at hydrogen fuel tanks, they often give the capacity in terms of "standard litres". However, I can't find a definition of what this is. I assumed this may mean a litre of hydrogen gas ...
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31 views

Can a Hydrogen Radical form in a chemical reaction?

Original question: During kolbe electrolysis of Formic acid, H2 is released at which electrode? What I thought: H2 will form at cathode due to reduction of water. But will the Formic acid decompose ...
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1answer
2k views

Hydrogen gas' reducing property

I just went though a reaction wherein hydrogen gas is liberated and hence restricts the product formed to ferrous and not ferric salt. I just want to know how H2 gas gets its reducing property? It has ...
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123 views

Why do we need to add hydrogen to amorphous silicon?

I was recently studying about Staebler-Wronski effect observed in amorphous silicon (a-Si). I realised it was due to imperfections in the lattice structure and breaking of Si-Si bond to Si-H bonds. ...
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Why is formic acid a stronger acid than acetic acid?

I am told that because the methyl group is electron donating in the conjugate base of acetic acid, this destabilizes the conjugate base by exacerbating the existing negative formal charge on the ...
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Comparing acidity in 3,4-dihydroxyfuran-2(5H)-one and 2,3-dihydroxycyclopent-2-en-1-one

I have two compounds with two hydrogens namely (a),(b),(c) and (d). I have to compare the acidity of the following hydrogens. My approach: I removed the hydrogen atoms one by one and compared the ...
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25k views

How explosive is hydrogen gas?

I want to electrolyze water to get oxygen and hydrogen. I want to mix them in a regular balloon and ignite it. How much hydrogen would you need in a 2:1 ratio with air for it to be dangerous? Is this ...
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Pre-Hydrogen Feature On the Output Of a Gas Chromatography Thermal Conductivity Detector

A candidate for "dark matter", predicted and now apparently detected to have both a higher thermal conductivity and higher diffusion rate than H2 is purported in this PowerPoint Presentation file. ...
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214 views

Pure Hydrogen and Dry Hydrogen Difference [closed]

Do pure and dry hydrogen are the same? What does dry hydrogen actually means. And what does pure hydrogen means.
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792 views

How to add hydrogens to a crystal structure?

PDB protein crystal structures most of the time lack hydrogen atoms. Usually I use PyMOL (h_add) but it does not always seem to be giving the correct result. What ...
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2answers
6k views

How to find the molecular weight of a given gas based on its density?

The density of a gas $\ce{X}$ is $10$ times that of hydrogen. In that case, what is the molecular weight of gas $\ce{X}$? Well what I've done up to now is this: The molecular mass of hydrogen is $M(\...
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1answer
202 views

Overlap matrix (H2 molecule, STO-3G) [closed]

I'd want to implement SCF method using Modern Quantum Chemistry (Szabo). But when I want to calculate overlap matrix for H2 (STO-3G basis) my results aren't equal to true overlap matrix that there's ...
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3k views

Would sodium explode in salt water?

I’ve seen the video etc of sodium being put into freshwater and the reaction of flames/small explosion but I wonder if the same reaction would occur if conducted in salt water such as the ocean.
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Slope of Graph of Wave Number vs inverse square of the principal quantum number(1/n^2) in Hydrogen Emission spectrum

What is the final expression we get for wave number in a hydrogen emission spectrum? Let us say for example from 6 to an orbit $n$. Considering that it is an emission spectrum, I think it would be ...
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119 views

Control the pressure of Hydrogen in a small container without the use of a pressure regulator

I had recently asked this question, and due to the comments and general consensus of safety concerns, I decided to re-ask the question, attacking the problem from another angle. The Problem I need ...
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1answer
104 views

Does the hydrohelium dication exist?

It is well-known that there exists the $\ce{He2^2+}$ dication, and also $\ce{HHe+}$ and $\ce{H2+}$ cations. But I could not find any definite information about the existence or inexistence of the $\ce{...
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125 views

Hydrogenation of 1-hexene with Raney nickel

For my high school senior chemistry project, I need to create and perform a lab. I've chosen to do the hydrogenation of 1-hexene with the catalyst of Raney nickel. I'm struggling because I'm not ...
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29 views

Hydrogen storage using activated carbons

On Wikipedia, a possibility of using activated carbons to store hydrogen is reported. According to the Wikipedia page, this solution can be used to store around 5 wt% by cooling down the hydrogen to -...
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390 views

Hydrogen's confusing purple glow

While reading about hydrogen on Wikipedia, I read that hydrogen has a purple glow in its plasma state. This confused me because although hydrogen is present in its plasma state on the sun, the sun ...
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1answer
203 views

Why is hydrogen not very electronegative? [closed]

I looked at my reactivity series and I have just realized that hydrogen and carbon are both included in the series, even though they are non-metals. So why is hydrogen more electropositive than ...
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Can reaction of gastric acid with swallowed things be dangerously exothermic?

Okay, okay. I know that swallowing a large enough amount of any substance would be considered dangerous. That isn't the point of this question, however. As you probably know, the stomach has ...
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1answer
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Can hydrides react with hydrocarbons? And why?

I have read there exist so called "magic" (super strong) acids which can provide a proton to saturated hydrocarbons, producing cation and hydrogen molecule. Can hydrides act in the same manner (pick a ...
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Why does the hydroxide ion have a negative charge?

I've been studying the roles of hydroxide & hydronium in acids and bases, and it was mentioned that a hydroxide ion (OH-) has a negative charge. Can someone give me a layman's explanation of what ...
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What is the sense of electronic configuration of an atom if an electron can be in any superposition of energy eigenfunctions?

I recently started learning abou the quantum mechanical explanation of hydrogen atom. In the derivation of the wave functions of hydrogen atom we find its energy eigenfunctions. But according to the ...
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270 views

Where to buy/How to build a Devanathan-Stachurski cell?

I'm preparing to do some hydrogen permeation tests to calculate the diffusivity of some iron samples. I would like to do this using the Devanathan-Stachurski cell, which consists of two cells, one ...
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Acids using different solvents [closed]

Many polar protic solvents exist and ionic compounds are able to dissolve inside these substances for the same reason as water. So, theoretically, if a substance were to steal a $H^+$ ion from a polar ...
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1answer
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My confusion regarding Hydrogen peroxide

In Hydrogen peroxide, the oxidation number of oxygen is "-1" instead of "-2". But it seems to me that, the oxygen atoms have '-2' as their oxidation number as each oxygen atom here is connected to a ...
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If electrolysis splits water, why does only either hydrogen or oxygen (but not both) bubble up on one pole?

If electrolysis splits water, then that means that $\ce{H2O}$ is split into $\ce{H}$ and $\ce{OH}$ or $\ce{O}$. How come that if a water molecule is split at e.g. the negative pole (anode), only the ...
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why hydrogen is so light?

I was studying about properties and behaviour of hydrogen and found that hydrogen is lightest element.It is so light that 1 litre of hydrogen at N.T.P weighs only 0.0980 grams. The first statement ...
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How is bonding in the trihydrogen cation and triatomic hydrogen possible?

According to wikipedia $\ce{H^+3}$ and $\ce{H3}$ are possible and have been synthesized. It says that $\ce{H^+3}$ is stable too. Can anyone please tell me how is the bonding possible? Hydrogen has a ...