Questions tagged [hydrogen]

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

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38 views

Hydrogen fuel cell purity / concentration

This is a chemistry/technology kind of question. Some PEM fuel cells work with a rated hydrogen purity of 99.99%. What would happen if the fuel cell stack is supplied with a hydrogen purity/...
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Is water hydronium and hydroxide? [closed]

In our chemistry lesson when learning about the Bronsted-Lowry definition for acids and bases, we came across the reaction... H2O + H2O -> H3O+ + OH- ...Where water is amphiprotic which means it ...
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Hydrogen safety during electro-chemical machining

I'm interested in doing some experiments with electro-chemical machining in my shop. The process involves running electricity through an electrolyte (salt water) to break down a metal anode (aluminum/...
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669 views

Smell produced in reaction of sodium hydroxide and aluminium

I was doing an experiment with $\ce{NaOH}$ dissolved in some $\ce{H2O}$ and aluminium. My textbook says that the following reaction takes place $$\ce{2 NaOH + 2 H2O + 2 Al -> 2 NaAlO2 + 3 H2}$$ It ...
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Nanoscale hydrogen batteries that use water-splitting technology

It was claimed in this article in 2019 that a nano-battery using water splitting technology is developed. It is described as: The battery gains its charge by interacting with water molecules present ...
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atomic structure - why only hydrogen be separately written in periodic table [duplicate]

The other exception is hydrogen. It has only one s-electron and hence can be placed in group 1 (alkali metals). It can also gain an electron to achieve a noble gas arrangement and hence it can behave ...
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Linearity of membrane resistance and contact resistance overvoltages in proton-exchange-membrane-water-elektrolyzer-cells (PEM-WE)

I am questioning why the cell component's resistance to the electrons (contact resistance) and protons (membrane resistance) flow follow the ohmic law. This assumption is made in recent papers on PEM-...
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water to hydrogen to water [closed]

I'm trying to find out if there is any loss of water when converting water to hydrogen and then back into water and can't find an answer anywhere I've searched. I understand that the water produced is ...
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1answer
77 views

What is the mass of a proton?

My textbook explains that the deviation from integer atomic mass is caused by mass difference between proton and neutron, which are $1.67262·10^{-27}$ kg and $1.67493 ·10^{-27}$ kg, respectively. If ...
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52 views

Ease of reaction of hydrogen with alkali and alkaline earth metals

The ease of reaction of group 1 metals with hydrogen decreases as we go down the group. But why lithium requires high temperature than sodium, potassium and rubidium? What is exactly "ease of ...
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Hydrogen atom orbital projections resemble to some Chladni figures! Mathematical reasoning?

Chladni figures are formed by sprinkling salt on a vertically vibrating membrane, f.e. . Some of them are purported to be projections of hydrogen atom orbitals f.e. 1s, 2s, 2p, 3d, e.t.c., f.e. One ...
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Why are protons more common than hydride ion?

I'm a high school student. I noticed $\ce{H+}$ ion is commonly present in my books while I didn't find any presence of $\ce{H-}$ ions in my books. However, I found on internet that $\ce{H-}$ also ...
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65 views

How can 2 molecular orbitals form simultaneously? [duplicate]

I understand (for example in the case of H2) that two s orbitals produce through constructive interference a bonding orbital and that the out of phase combination of two s orbitals leads to ...
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1answer
74 views

Cleaning with Hydrogen Peroxide is not a chemical process?

Reading here: if the peroxide does seem to help is that the bubbles forming and foaming is helping dislodge tiny particles in the cracks of the mineral. Is this the case in general for cleaning with ...
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Hydrogen concentration measurement without gas chromatography

Please suggest ways to measure $\ce{H2}$ concentration in a sample of gas containing $\ce{HCl},$ $\ce{CH4},$ $\ce{N2},$ $\ce{CO2}$ and trace amounts of chlorosilanes without GC. The problem is that I ...
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How can a hydrogen atom ever emit an X-ray photon?

From Scientific American, February 2014: The Proton Radius Puzzle: ...we had to tune the laser so that it came in with exactly the right amount of energy. The atom would make the jump to the higher ...
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Why do poisoned catalysts (Lindlar, nickel borate) result in partial hydrogenation of alkynes?

I read that alkene is more reactive than alkyne, so in hydrogenation of alkynes, it's difficult to isolate the alkenes. But with poisoned catalysts like Lindlar's catalyst or Nickel-Boron (Ni2B), they ...
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1answer
83 views

Removing hydrogen bubbles by reacting them away

I have a microfluidics problem where hydrogen is forming tiny (nanometer-scale) bubbles which cause problems. The hydrogen is a reaction byproduct that comes from n etch between silicon and TMAH. The ...
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573 views

Can hydrogen peroxide reduce ferric ion to ferrous ion?

I have studied that hydrogen peroxide always oxidizes ferrous ion to ferric ion (source of study : NCERT Chemistry Part II, Textbook for Class XI), but a question came in IIT JEE 2015 which states: ...
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1answer
64 views

How is most probable radius in quantum mechanical model equal to Bohr's radius in hydrogen atom

Most probable radius in 1s orbital for hydrogen electron is $\pu{0.529E-10 m}$ which is Bohr radius. But energy of electron in hydrogen atom is proportional to mean radial distance in atom. In this ...
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1answer
35 views

Which is more efficient way to generate energy using hydrogen: direct hydrogen combustion or through fuel cell? [closed]

Which is more efficient way to generate energy using hydrogen: direct hydrogen combustion or through fuel cell? Please explain so that even a primary school student can understand.
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1answer
102 views

Can someone give me examples of Hydrogen's ionic bonding? [closed]

When I google for examples I find examples of Hydrogen bond. Theoretically, Hydrogen should be able to bond with compounds with a much higher or much lower electronegativity than 2.2. I am 8th grade ...
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How to Build Hydrogen Atoms in MOE using SVL

I'm working on automating a process in MOE using SVL commands. I've got pretty much everything worked out, except I can't seem to find anything for building hydrogen atoms using an SVL command (...
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1answer
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What is Nascent Hydrogen? [duplicate]

I am currently studying preparation of Alkane from Alkyl Halides (By Reduction) But the term "Nascent Hydrogen" Confuses me after reading diffrent threads and stuff Please help :)
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Does lead carry the negative charge in plumbane?

It says in Wikipedia that lead tetrahydride or hydrogen plumbide or plumbane ($\ce{PbH4}$) is supposed to have lead in its -4 state and the hydrogen is in its +1 state because supposedly lead has a ...
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27 views

What determines the consistency of hydrogen foam when reacting aluminium with sodium hydroxide solution?

I was using $\ce{NaOH}$ solution to remove hardened grease from my stove burners, and it began to generate a lot of bubbles, some of which merged into a big bubble and erupted into the surface, but ...
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A contradiction in the nucleophilic attack of hydride ion based on charge densities

On page 130 of Organic Chemistry by Clayden, it is stated that Nucleophilic attack by the hydride ion, $\ce{H-}$, is an almost unknown reaction. This species, which is present in the salt sodium ...
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Why does hydrogen burn with a pale blue flame while its emission spectral lines are red in colour?

I was studying oxidising flames and realized that sodium burns with a bright yellow flame the wavelength of which is around 588 nm. Then I searched for emission spectra of sodium and found that the ...
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78 views

What is the activation energy of creating molecular hydrogen from atomic hydrogen?

If molecular hydrogen is dissociated, or two hydrogen atoms in space collide, how much energy (in $\pu{eV}$, or perhaps $\pu{kJ/mol}$) does it take for an $\ce{H_2}$ molecule to form?
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How to learn about hydrogen fuel cells [closed]

Problem: I am a physics and engineering major going to work for an engineering company this summer. My boss wants me to do a comprehensive review of hydrogen fuel cells and report back on the cutting-...
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What is the product of reaction between 2‐cyclobutyl‐2‐isopropyl‐1,3‐dioxane and hydrogen with Raney nickel?

I have 2‐cyclobutyl‐2‐isopropyl‐1,3‐dioxane (alcohol protection) and I have to react it with $\ce{H2}$ and Raney nickel, but I don't know what the product would be. I have seen a similar reaction ...
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61 views

Why are hydrides of transition metals called hydrogen-deficient?

My textbook states: Metallic hydrides are formed by many d- and f-block elements. Unlike saline hydrides, they are almost always non-stoichiometric, being deficient in hydrogen, for example, LaH$_{2....
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104 views

Molecular geometry of BaH2 according to VSEPR theory

I am asked to predict the correct molecular geometry of $\ce{BaH2}$ according to VSEPR theory. I assumed that it is linear due to barium being an alkaline earth metal and therefore not having any lone ...
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1answer
81 views

What is the anodic reaction of aluminum in water

Standard electrode potentials are reported for materials that are not usable as actual electrodes in water because they react spontaneously and rapidly. https://www.engineeringtoolbox.com/electrode-...
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Reaction between barium peroxide and hypochlorous acid

When $\ce{BaO2}$ reacts with $\ce{HClO},$ the question tells us that that oxygen, barium chloride and one other product is formed. The equation I came up with is $$\ce{BaO2 + 2 HClO -> BaCl2 + 2 O2 ...
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161 views

The rusting of steel may be promoted by brushing with HCl followed by brushing with hydrogen peroxide solution. What is the chemistry involved?

A welder showed me a way of promoting rust on steel by brushing on muriatic acid and then a hydrogen peroxide / water solution. What's going on, chemically speaking?
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Question on Hydrogen Balloon

I tried to extract hydrogen for my kid's birthday, by mixing caustic soda with water and aluminum foil (mixed in a glass bottle). A lot of heat and (hopefully)hydrogen was released. However, within 2-...
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hydrogen spectrum

In the spectrum of atomic hydrogen, several lines are generally classified together as belonging to a series (for example, Balmer series, Lyman series, Paschen series), What is common to the lines ...
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142 views

Lost track of the hydrogen in step 3 of the Krebs cycle

I'm trying to follow the Krebs cycle step by step, accounting for the number of hydrogens in each molecule before and after reactions. I've run into a problem starting from step 3. Isocitrate has ...
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1answer
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Does the volume of water involved affect rate of electrolysis?

I am working on the design for a homemade PEM electrolyzer, and my goal is to make it as compact as possible, so as to allow easy transport. My question, as it relates to that, is whether - with the ...
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99 views

Azimuthal Quantum Number [closed]

In the radial equation of hydrogen atom the differential equation is described by But why is l taken to be integer. I know the principal quantum number n correspond to energy levels so that's why it'...
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105 views

Is the Hydrogen spectrum only an emission spectrum?

In a statement question it was stated that hydrogen spectrum is an emission spectrum and the scheme considered it to be ture. But my argument is that it can be both emission and abosorption spectrum. ...
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501 views

Can H+ ion exist independently? [duplicate]

Can H+ ion exist independently since it does need to form any bonds.Why do we say that it needs to be in H30+ ion form?
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1k views

Which is more stable: Ortho or Para Hydrogen? [duplicate]

It is known that Para-Hydrogen has opposite spin and Ortho-Hydrogen has same spin. Therefore, the energy of Para-Hydrogen is lower than that of Ortho-Hydrogen. Therefore, the stability order should be:...
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367 views

What does *oxidizing* have to do with *hydrogen*? [closed]

An oxidizing acid is a Brønsted acid that is a strong oxidizing agent. All Brønsted acids can act as oxidizing agents, because the acidic proton can be reduced to hydrogen gas. (source: Wikipedia) ...
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Naming and structure of PtCl4.2HCl (complex/coordination compound)

Given that $\ce{PtCl4.2HCl}$ when reacted with excess of $\ce{AgNO3}$ produced zero moles of $\ce{AgCl}$, I understand that all the chlorine atoms are inside the coordination sphere. But what will the ...
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234 views

Average bond energy of H−F and H−O hydrogen bonds

Which of the following hydrogen bonds (shown by the dotted line) has the highest average bond energy? A) $\ce{F-H\bond{...}F}$ B) $\ce{F-H\bond{...}O}$ I am thinking the answer is $A$ since the ...
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53 views

Is there more efficient reaction for generating hydrogen rather than HCl+Al [closed]

I want to generate hydrogen to acquire known pressure inside of an object. I have calculated required mole number for hydrogen using the ideal gas equation by giving wanted pressure, volume and ...
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4answers
7k views

At what pressure will hydrogen start to liquefy at room temperature?

I want to increase a fixed-size object's internal gas pressure by generating hydrogen in it, but I could not find the proper phase diagram for it. So I am wondering how high pressures I can get.
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How does the position of hydroxyl group in a nucleotide monomer affect the dehydration synthesis of nucleotides?

In dehydration synthesis of nucleotides, the hydrogen atom from the 3' carbon on the deoxyribose sugar of one nucleotide reacts with the hydroxyl group on the phosphate group of another nucleotide to ...

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