Questions tagged [electrochemistry]

The branch of chemistry that deals with the study of redox reactions and how they can be applied to generate electricity (in electrochemical cells) and to carry out non-spontaneous reactions using electricity (electrolysis).

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184 views

Some materials emit more photoelectrons than others - why?

Again, I'm a physicist turning to chemists (so bear with me). So I've been measuring some materials by changing the wavelength of the incident light on the material and I have a detecting tip like in ...
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164 views

What exactly is an “electron-sponge”?

What exactly an "electron-sponge" [behavior/action/property/system] nickname is, and what makes a material an "electron-sponge" (preferably, quantitatively)? From what I found, it's typically a ...
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1k views

Nernst equation for a fuel cell when gases are stored separately

I have run some tests with a PEM fuel cell and the voltage we have found was $1.44\ \mathrm{V}$. Given that the standard potential for a fuel cell is $1.229\ \mathrm{V}$ what is causing the difference ...
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1answer
478 views

Does phosphoric acid remove stainless steel electropolished layer?

Electropolished stainless steel has a high corrosion resistance due to the oxide film that is created during electropolishing. The film mainly consist of chromium(III) oxide. Phosphoric acid is ...
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33 views

Removal of nickel plating on MgB2 without damaging the boride?

I need to remove a nickel plating of a MgB2 wire without causing damage to the MgB2. I felt that electrolysis is the best method but I do not know what electrolyte to use for this. I also need to coat ...
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1answer
51 views

Protons and osmotic potential

In a hypothetical enclosed membrane only permeable to water (including hydronium), where inside the pH is lower than the outside, would water move inside?
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721 views

What are the factors that affect the redox reactions?

In my work, I used $\ce{Co(OH)2}$ and $\ce{Ni(OH)2}$ as an active materials to fabricate as symmetric supercapacitors in which I used 1-butyl-1-methylpyrrolidinium dicyanamide as an electrolyte. From ...
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128 views

Thought Experiment: Is it possible to preserve the charge imbalance present during molten lead(II) bromide electrolysis?

Suppose I were to electrolyse some molten lead(II) bromide. According to what I have been taught, the lead ions travel towards the cathode and are reduced at it, while the bromide ions are oxidised at ...
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2answers
202 views

Is there a potentiometric method for monitoring salt formation in organic solvent?

I work in a pharmaceutical R+D lab, and currently aim to develop a validatable potentiometric method for determining the optimal amount of acid to add to a basified small organic molecule for ...
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271 views

Reduction of vanadyl ion

I want to reduce vanadyl to vanadium (III), can somebody please suggest some appropriate methods for it? I am trying to make a redox flow battery for a project but I have only vanadyl sulfate.
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33 views

Problem interpreting CV diagram in a paper

I am an undergraduate materials science student. I am currently preparing to conduct some research over the summer on alkaline electrolyte membrane fuel cells and have been reading some papers to get ...
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60 views

Is pH in a charged hydrogel and its supernatant solution constant?

Let us assume we deal with ideal systems without interactions. The gel phase and the supernatant solution phase are in thermodynamic equilibrium. The supernatant solution shall consist of different ...
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53 views

Meaning of electrochemical vs nonelectrochemical steps

Can someone please explain to me what is meant by an electrochemical reaction step and how it differs from a nonelectrochemical reaction step in the same overall reaction in the context of ...
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52 views

Choosing electrodes for corrosive environments

Background I'm building a watering robot for my household plants. For the purpose of measuring the moisture content of the plant I intend to use a resisitive approach where I pass an electric current ...
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807 views

Concept of Limiting Current

I am investigating the current output from an electrochemical cell. The electrochemical cell can be broken down into several stages, for example: Diffusion of reactants across a capillary Diffusion ...
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32 views

Is electric current always necessary to make cathodic protection possible?

Can a cathodic protection system still work if there is no current between the anode and cathode?
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204 views

Why does the electrolyte used in Lechlanché cell turn blue?

In my school there are jars which are turned into Lechlanché cells. Basically the cell has aqueous ammonium chloride solution as the electrolyte which is obviously transparent in the beginning. The ...
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325 views

Conductivity of electrolyte solution

I found a relationship online between the conductivity of electrolyte and current. $$i = F \sum_i z_i N_i = F^2 \left( \sum_i z_i^2 u_i c_i \right)\nabla\phi = -\kappa\nabla\phi \qquad \kappa = F^2 \...
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543 views

Why does the open circuit voltage of a battery decrease with increase in pH of electrolyte, but the voltage across a load increase?

I tested a cell which had aluminum sulfate as its anode electrolyte (12 grams aluminum in 50 mL water and a pH of 3.2), and potassium hydroxide as the cathode electrolyte (5 grams of KOH in 200 g of ...
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888 views

An alternate purification process for sugar separation form bee honey?

Bee honey contains 75% sugars (Fructose, Glucose, Maltose, Sucrose and others), some water and low amount of different compounds (up to 5%) Wiki. Basic purification is done by addition of phosphoric ...
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742 views

Calculation of optimal current density

I'm trying to figure out what my optimal current density would be in respect to the limiting current density. How do you calculate concentration polarization and limiting current density in an ...
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1k views

Does the temperature of water change during electrolysis?

Applying an electric potential to impure water splits water into its constituents H/O. Does the temperature of the electrolyte change during this electrolysis?
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52 views

Galvanic Cell Temperature Dependence

I'm currently studying the temperature dependence of the following cell: $\ce{Cu_{(s)} + 2Ag^{+}_{(aq)} <=> 2Ag_{(s)} + Cu^{2+}_{(aq)}}$ ($E^⦵ = \pu{+0.46 V}$) Experimentally, I recorded the ...
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29 views

The physical intuition behind some simplifications in electrochemistry

Find the standard reduction potential of $$\ce{AgIO3(s) + e- <=> Ag(s) + IO3-}.$$ $K_\mathrm{sp} = \pu{3.1E-8},$ and the standard reduction potential of $\ce{Ag +e- <=> Ag(s)}$ is $E = \...
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79 views

How can I determine the electrode potential of ethanoic acid redox reaction?

I'm conducting a research paper on the effect of surface area ratio from anode to cathode and the electrode material on the rate of electrolysis of ethanoic acid by measuring the volume of carbon ...
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26 views

Rate of cathodic reaction vs Tafel slope

One of my reference engineering books says that for the cathodic protection process (in seawater): Al $\rightarrow$ Al$^{3+}$ + $3e^-$ (anode, setting the protection potential at about -900 mV SCE) ...
3
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1answer
225 views

Why does magnesium deposit during electrolysis of a molten mixture of MgI2 and AlBr3?

During the electrolysis of mixed salts, I read, and was taught, that the cation with a higher ionization energy would deposit at the cathode. I was also told that you cannot use the standard electrode ...
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110 views

Electrolytic cell to remove soft solder from silver?

Hi my chemistry is pretty dire but have vague idea that an electrochemical cell could be used to remove soft solder (lead/tin probably) from a piece of sterling silver in need of a repair. The ...
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41 views

Question about the composition of a 1902 non-polarisable electrode diagram by Jagadis Bose

In his work, "Response in The Living and Non-living" (1902); page 6, Jagadis Bose describes a method for detecting nerve response. He explains that he uses iso-electric contacts with no current in the ...
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73 views

Removing Tungsten Trioxide from Tungsten Electrode

I need a very sharp tungsten electrode, and I think radial electrochemical etching with sodium hydroxide is the way to go. The problem therein (I think) is that the etching will cause an oxide layer ...
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305 views

Does Reduction Potential affect rate of electrolysis

I am currently doing a project on electrolysis, and I was wondering if the reduction potential (ie. $E^0$) will affect the rate of electrolysis. In other words, across different cells with differing $...
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1answer
56 views

Can I anodize an aluminum coating on steel to have better corrosion inhibition for the steel?

I am planning to coat aluminum on steel and I want to give the steel its maximum corrosion protection. Is anodizing the coating necessary?
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159 views

White mucous substance forming around iron paper clip during electrolysis

I'm using a graphite cathode and an iron paper-clip anode, in a saltwater solution, basically to produce rust. I've done this before with no complications, but this time I noticed a white, mucous ...
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429 views

Understanding Chemical Potential (Li-ion)

Can anyone help me to understand what the "Chemical Potential" is? I can see that in batteries the electrical energy is stored as "chemical potential", according to this: Li-ion ...
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241 views

Why does chromium metal not react with a solution of Mg^2+ even though their standard cell potentials produce a net positive voltages?

Write net equations for the spontaneous redox reactions that occur during the following or NONE if there is no extensive reaction. Use the lowest possible coefficients. Include states-of-matter under ...
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743 views

How to calculate the thickness of the double layer at an electrode

I need help calculating a double layer thickness. In this situation two insulated planar electrodes are placed in an electrolyte (in this case drinking water) and a voltage is applied to them of 10V ...
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44 views

Does Fluoroborate gets used up in Electroplating

I've been working on Tin electroplating on the side for a while now. I've formulated a mix from my usual electroplating formula template. The mix stubbornly keeps on having the Tin ions form Tin ...
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64 views

What is the voltage dependence of the thickness of oxide coating through anodising?

In titanium anodising, solid titanium reacts with the oxygen formed at it's surface (to form titanium(IV) oxide or $\ce{TiO2}$) through the electrolysis of water. Experimentation and research has ...
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50 views

How do I calculate the viscosity of a mixture of toluene and isopropanol?

I am trying to understand why my nanoparticles will only electrophoretically deposit in a non-polar solvent and a non-polar/polar solvent mix but not in the polar solvent. I am hoping to use zeta ...
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117 views

Photoelectrochemical (PEC) water splitting

I'm starting to prepare for my research project on photoelectrochemical (PEC) splitting of water into H and O using (F doped) titanium dioxide as the photoanode. I've been unsuccessfully searching in ...
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400 views

How will the transference number of H+ ion in a dilute solution vary as temperature increases?

I know that transference number depends on Ionic mobility, which depends on temperature. But is there any equation which describes the relation of Transference number and temperature, any ions like H+....
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1answer
54 views

Standard electrode potential of copper disproportionation

I am having some difficulty with the below. It says the standard potential for $\ce{2Cu+ (aq) -> Cu (s) + Cu^2+ (aq)}$ is $\pu{0.36 V}$. The relevant half equations are: $\ce{Cu+ + e- -> Cu}$ (...
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36 views

Why I get acidic solution at brine anode?

I have decomposed $\ce{NaCl}$ solution (brine) with electrolysis and yield $\ce{NaOH}$ at cathode, at anode I got acidic while expected was $\ce{NaClO}$ (alkaline) if it is $\ce{HOCl + HCl}$. Where ...
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38 views

Correlation between redox pseudocapacitance, surface area, and cell potential with metal oxide electrodes

I'm having difficulty intuitively reconciling two different ideas concerning metal oxide thin films in contact with aqueous solutions: 1) that charge storage by both redox pseudocapacitance and ...
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31 views

Cyclic voltammetry for irreversible reactions

I'm new to electrochemistry and I was wondering two things, sorry if these two problems are trivial but I just can't find anything close to this in the literature. First, the following reaction is ...
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28 views

Why isn't the chemistry of a zinc-air battery (meaningfully) hindered by an activation energy barrier?

Virtually every source I've read pertaining to zinc-air batteries explain the chemistry of it either using these formulae or a simplified version of them: $$ \begin{align} &\text{Anode:} &\...
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30 views

What is the diffusion limiting current density in comparison to rotating electrodes or fuel cells with pumps/stirrers?

If an electrolytic fuel cell operates in an acidic liquid electrolyte and electrons are supplied to a catalytic electrode so that the protons in the liquid solution will react and produce hydrogen gas,...
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1answer
31 views

Determining the Energy Density of a Battery given the anode and cathode

everyone, I'm using nanohub's introduction to the material science of rechargeable batteries course to do some self-studying until I can go back into the lab. On one of the practice problems, it asks ...
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77 views

Effect of charge density on electrolysis of dilute sulphuric acid

I am told that if electrolysis of dilute sulfuric acid is performed under high charge density, then the following reaction takes place at anode instead of evolving oxygen: $$\ce{2 HSO4- -> H2S2O8 +...
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18 views

Can I use an electrolyte containing a different cation from the anode when doing an electroplating experiment?

For example, I want to purify copper. So the anode will be impure copper and cathode will be pure copper. However, instead of using copper sulphate/halides/nitrate solution, can I use magnesium ...

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