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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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Electrolysis of concentrated Sulfuric acid, Reduction of sulphate ion

While studying electrolysis, I came across the oxidation reaction of SO₄²⁻ where it oxidizes into S₂O₈. I don't understand why it prefers to dimerize and form S₂O₈ instead of just staying in the SO₄ ...
Advait K's user avatar
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Determining an unknown E° from two similar half ox/redox reactions

Use the oxidation half-cell and reduction half-cell, $\ce{Cr^3+/Cr^2+} = \pu{0.424 V}$ and $\ce{Cr^3+/Cr2O7^2-} = \pu{1.32 V}$, to determine the $E^\circ$ for $\ce{Cr2O7^2-/Cr^2+}$: a. $\pu{-1.75 V}$ ...
Robertsson's user avatar
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1 answer
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Effect of temperature on voltage of a galvanic cell can't use Nernst equation? [closed]

Is it worth investigating the effect of temperature on EMF in a galvanic cell? I suspect the change will be very very small and maybe impossible to test precisely in a high school lab. This article ...
Mr. Mister's user avatar
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Confusing Question on half cells [closed]

I have a question: Why do we use Metal-Insoluble Salt Anion half cell when we already have a metal-metal ion half cell? I couldn't understand why?
ANNJEE's user avatar
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Change in Gibbs energy for lithium redox reaction

I was reading an electrochemistry book by Thomas F. Fuller, in this book the thermodynamic values for the lithium redox reaction at standard conditions are the following: Reaction $\Delta G^o$ [kJ/...
RMS's user avatar
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-5 votes
0 answers
36 views

What exactly is Electrode Potential in a Galvanic cell? [closed]

My textbook states that it's the potential difference between an electrode and the electrolyte in a half-cell. My doubt arises because the salt bridge already provides enough ions to neutralize the ...
Gopal Kaushik's user avatar
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Why can't chromium (chrome) be coated on objects with simple hot-dip galvanization?

I have had to learn a lot about why it is difficult to do electroplating with chromium, it's low electrolytic efficiency, etc., but one simple thing eludes me... Why involve electrochemistry at all? ...
Kurt Hikes's user avatar
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10 votes
2 answers
796 views

Electrolysis experiment with CuSO4

I'm doing an electrolysis experiment with an aqueous solution of copper sulfate $\ce{CuSO4}$ and graphite electrodes. I thought that only metallic copper was formed at the cathode (and oxygen at the ...
Andrea's user avatar
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6 votes
1 answer
387 views

Is the positive electrode of voltaic cell actually positive or just less negative?

Is the positive electrode of a voltaic cell actually positive or just less negative? Because it seems to me that the positive electrode is just less negative relative to the negative electrode and ...
funso's user avatar
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2 votes
1 answer
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Why Is HOI a weaker acid than HOCl?

In HOI, the oxygen would be more negatively charged than the oxygen in HOCl because iodine is less electronegative than chlorine. Thus the O-H bond in HOI would be more polarized, which would mean it ...
Kryptic Coconut's user avatar
-1 votes
1 answer
70 views

Electrolyte in Electrolysis of CuSO4 [closed]

I have 2 questions regarding electrolyte used in electrolytic refining of copper: I was reading metallurgy of copper and I noticed that in electrolytic refining we use acidified aqueous $\ce{CuSO_4}$ ...
Amit's user avatar
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Devanathan / Stachurski cell, hydrogen permeation in palladium

The cell mentioned in the title is a couple of electrochemical cells separated by a metal diaphragm. On the surface of the diaphragm, on one side, hydrogen is evolved. The amount that permeates is ...
Doriano Brogioli's user avatar
3 votes
1 answer
53 views

What happens during electromigration in low concentration electrolytes?

I'm not sure if my understanding is correct, please correct me if there is something wrong. Considering a 2 electrodes system with a constant voltage applied between both electrodes and with no ...
An29's user avatar
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1 vote
1 answer
50 views

What exactly is the area used in the equation R=ρl/A to find the resistance of an electrolyte?

My textbook says the resistance $R$ of a water column filled with some electrolyte is $$R=ρl/A,$$ where $ρ$ is the resistivity, $l$ is the distance between the electrodes, and $A$ is the area of cross ...
Shivang Thakur's user avatar
2 votes
1 answer
906 views

Ultraviolet Movie [closed]

What is the best material for a screen using an Ultra-violet light projector? I need a material/screen that can convert UV light into a visible light to best look like a normal movie theater screen ...
Justintimeforfun's user avatar
-1 votes
1 answer
40 views

How does salt water conduct current? [closed]

Think of a simple system - a battery is connected to two Pt electrodes that are both submerged in a glass of pure water with some NaCl. You always hear people say that in the conductors (leads/Pt ...
Yuri Shakhman's user avatar
1 vote
1 answer
79 views

How does cell potential change with temperature for positive enthalpy and negative entropy?

A recent United States National Chemistry Olympiad question asked: A certain voltaic cell has a standard cell potential that increases with increasing temperature. Which best explains this ...
unstable's user avatar
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8 votes
1 answer
707 views

What happens to an ongoing electrolysis when you turn off the battery?

Suppose you do an electrolysis experiment, where you have two carbon electrodes, a battery, and water in a which a strong electrolyte, like NaCl, is dissolved. The circuit is closed and the ...
dark_ursus's user avatar
2 votes
0 answers
32 views

Is there any method to make sure a electroplated layer of iron oxidizes into magnetite (Fe3O4) instead of hematite (Fe2O3)?

I am currently electroplating iron on copper using a DIY setup in my lab. Steel sheet as anode with electrolyte having 5% acetic acid with sodium carbonate to form sodium acetate and added some NaCl ...
assasinchop7's user avatar
0 votes
1 answer
53 views

Does electrode material affect efficiency of water electrolysis?

I've been creating hydrogen via electrolysis of water, using pure nickel strips as electrodes, in a sodium hydroxide solution. (These nickel strips are commonly sold for use in battery packs). I'm ...
MadScientist's user avatar
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2 answers
80 views

Fundamental understanding of electrode potentials

The electrical double layer, is commonly used to describe the origins of electric potentials that is fundamental to electrochemistry. This model is quite outdated from my understanding, but it is ...
Stark's user avatar
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0 votes
2 answers
33 views

Electrolysis to refine metals

Why does the cathode get bigger and the anode smaller when we use copper electrodes for the electrolysis of Copper Sulphate? Why does the anode not receive electrons from the anions (e.g Sulphate and ...
21e1e2's user avatar
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13 votes
3 answers
2k views

Do electrons really hang around the electrode while ions go take a swim?

This answer to this post addresses "what happens if you dip a single zinc electrode into some electrolyte solution." It explains that However, though the zinc ion can diffuse through the ...
Buck Thorn's user avatar
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2 votes
2 answers
116 views

Does the electric field of a battery exist before a wire is connected outside?

Imagine a galavanic cell. What I am wondering is, what causes the inital oxidation of the less nobel metal to occur initally. Is the electric field there before you connect a wire, which would allow ...
Niclas's user avatar
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-3 votes
1 answer
74 views

Why is AgCl considered a good electrolyte? Isnt it sparingly soluble?

My textbook says AgCl has degree of dissosciation as almost 1 but its sparingly soluble. While solving to find Ksp of AgCl using kohlrauschs law we have said that molar conductivity of sparingly ...
Catastrophic Cow's user avatar
0 votes
1 answer
65 views

In electrochemisty, we write delta S= nF(dE/dT)p (at constant pressure), is (dE/dT)p cell constant?

My lecturer stated that dE/dT at constant pressure is cell constant, but isnt cell constant of a cell (l/A) the units don't match, is there any other cell constant that he might be talking about?
Catastrophic Cow's user avatar
2 votes
1 answer
120 views

Deriving Nernst Equation for a hydrogen-oxygen Fuel cell

Reading across electrochemistry books (particularly the fuel cells chapter of the book "Alternative energy systems and applications" by Hodge) I came across the following formulae: $$\Delta ...
RMS's user avatar
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0 answers
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Simple Calculation of Potentials for a hydrogen-oxygen Fuel cell, unexpected results from book example

I am reading "Alternative energy systems" by Hodge. On the fuel cell section, the author has an example for calculating the potential required for the fuel cell as a function of temperature ...
RMS's user avatar
  • 203
1 vote
3 answers
86 views

How to deduct the concentration of chloride in a silver/silver chloride electrode, given the cell notation

I have this cell notation: $$ \ce{Zn|ZnCl_2(0.05M)||AgCl(s)|Ag} \tag{1} $$ What is the physical shape of this cell? I know $\ce{AgCl}$ has very low solubility, and the problem has no concentration on ...
Martín Montoto Fernández's user avatar
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0 answers
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Electrolytic Substrate modification to enhance corrosion resistant of reactive metal

So, I was working on a project lately. The project I was working on involves the utilization of inexpensive, non-toxic, and inert electrodes. Unfortunately, the only substrates I have access to are ...
Ananiya J. Kesto's user avatar
-3 votes
1 answer
65 views

Aqueous electrons in electrochemical cells [closed]

In the context of a zinc-copper electrochemical cell, zinc atoms at the anode are oxidized, releasing electrons and forming zinc ions that dissolve into the solution ($\ce{Zn(s) -> Zn^{2+}(aq) + 2e-...
Kris's user avatar
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4 votes
2 answers
553 views

Why aren’t electrolyzers made like this(two inter-locking coils)?

The maximum current(based on how long you want your electrolyzer to last) is based on the electrode size according to my minimal research. The larger the electrode the more current is allowed. So why ...
Anish Kommireddy's user avatar
0 votes
1 answer
46 views

Temperature dependence of enthalpy in electrochemistry

I've been trying to use Kirchoff's law to determine the difference in the enthalpies of electrochemical reactions at different temperatures for a general electrochemical process. So here's my progress:...
Cognoscenti's user avatar
0 votes
1 answer
56 views

Neglected partial pressures dependence of water splitting

I am studying electrochemical water splitting and I have a huge doubt. The standard redox potential for the total reaction is 1.23 V, but this is in standard conditions, where the hydrogen and oxygen ...
th3f4tk1ng's user avatar
-3 votes
1 answer
110 views

Doubt regarding Gibbs energy and Electrode potential

I have a doubt regarding the relation between Gibbs energy change and E cell, especially when calculating for redox reactions. This is a question I have seen on a website called "ExamSide ...
BK01's user avatar
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2 votes
1 answer
92 views

Do solvated electrons short circuit the electrolysis of liquid ammonia

If attempting the electrolysis of liquid ammonia using NaNH2 as an electrolyte. It is understood that Na+ will form solvated electrons. I understand that these solvated electrons can dramatically ...
Thomas's user avatar
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-1 votes
1 answer
146 views

Can Sodium atom (Na not Na+) be considered a free radical?

By definition "Free radical is a chemical species that has a single unpaired electron in the outermost orbit". Sodium atom also has a unpaired electron in outermost shell and it is also ...
Afzaal's user avatar
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2 votes
1 answer
56 views

AC voltage drift

I am applying AC current to a capacitive electrode and recording the change in voltage over time. I have observed a voltage drift that does not follow any consistent pattern. Sometimes, the drift is ...
Simon's user avatar
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2 votes
1 answer
53 views

Would microelectrodes reach a steady state current if convection is negligible and only pure diffusion occurs?

Assuming a two dimensional Cottrell type problem with a micro-electrode and a high enough applied potential so that concentration of the consumed redox species would be zero near the surface. ...
Youssef Khar's user avatar
2 votes
0 answers
44 views

Alternative pH sensing methods?

I am looking for alternative methods to measure the pH of water (swimming pools, tap water, rivers,...) with (ideally) the following properties: Durable: no maintenance or calibration required for 5-...
emdura's user avatar
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1 vote
0 answers
44 views

Faraday's law of electrolysis and equivalent weight

I came across this question in an exam: The mass of silver ($M(\ce{Ag}) = \pu{108 g mol-1}$) displaced by a quantity of electricity which displaces $\pu{5600 mL}$ of $\ce{O2}$ at STP will be _____ $\...
Anne's user avatar
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0 votes
2 answers
129 views

Why is there a need to have H₂(g) gas even at the cathode of SHE (standard Hydrogen electrode) / Galvanic cell?

In almost all resources I have come across, I have noticed that there is an initial amount of $\ce{H2(g)}$ maintained at 1 bar, kept at the cathode of the standard hydrogen electrode, But what is the ...
Sai's user avatar
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-2 votes
1 answer
74 views

How does electric current flow in daniell cell?

The actual question in my mind is that ……..at anode zinc oxidises to form $\ce{Zn^{2+}}$ and $2$ electrons, but it should be the same case at cathode because copper should also oxidise to form $\ce{Cu^...
Physics student's user avatar
3 votes
1 answer
135 views

Electrolysis of benzyl alcohol in methanol

I am conducting following electrochemical experiment on Au wires in organic medium: I suppose the anodic reaction goes through a benzaldehyde intermediate: The cathodic reaction is hydrogen ...
Mäßige's user avatar
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0 votes
0 answers
45 views

Disproportionation reactions

Are there any examples of a disproportionation reaction being harnessed to do useful electrical work? It is of course possible in a comproportionation reactions, such as a lead-acid cell.
Bill Harrison's user avatar
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0 answers
33 views

How to coat stainless steel?

I am trying to coat stainless steel with carbon black. I am using Polyvinylidene fluoride PVDF 2% as a binder. I dip and I heat at 100C. The coating that comes out is very fragile where you can blow ...
Anwer Ak's user avatar
-2 votes
2 answers
111 views

How do electrons travel through a fuel cell or flow battery with multiple cells?

I understand that if you have a fuel cell or flow battery with a single cell that electrons will go from the electrode and through an external circuit across the load which the fuel cell / flow ...
DavePiae867's user avatar
1 vote
0 answers
42 views

Increasing energy density for flow batteries with water based electrolyte?

Given a flow battery with a water based electrolyte, would it be possible to increase the energy density of battery by precipitating the redox active species from the anolyte and catholyte solutions? ...
Lance Collins's user avatar
-2 votes
1 answer
117 views

Inconsistency in between Nernst Equation and Gibbs Free Energy Equation [closed]

Part 1 - Derivation of the Gibbs Free Energy Equation: [copied from this] Using the fundamental equations for the state function (and its natural variables): \begin{align} \mathrm{d}G &= -S\...
Asmit Karmakar's user avatar
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0 answers
38 views

Using biochemical standard state versus chemical standard state

Can I use the table below to calculate the standard cell potential, $E^{\circ}$, of ethanol oxidation to acetaldehyde (EtOH + 1/2O2 $\rightarrow$ Acetaldehyde + H2O)? Does it matter that the half-...
GMoss's user avatar
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