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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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How&why does change in concentration affect cell potential

I'm a bit confused about why (in 1c) if the air pressure is lower, and there is a lower concentration of oxygen, why the cell potential decreases. It checks out fine with the Nernst Equation, but ...
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Electrochemical cells. Why is a salt bridge needed at all when the system is open? [closed]

I get that the purpose of salt bridges is maintaining the amount of negative and positive charges in the solutions of two connected half-cells when electrons flow from one to the other. But when the ...
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43 views

Current in a Lithium Ion Battery

I am trying to find the current transferred to the anode and cathode of a Lithium Ion Battery at different voltages. I know the temperature (approximately) of the battery, the battery's starting ...
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Detection limit of selective ion electrodes

I've been studying about the selective ion electrodes and I came across a question which I seem to not be able to answer. It has to do with why the detection limit for iodide ions is lower than the ...
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221 views

Why do the Metal Ions in an Electrochemical Cell Not Pass Through a Salt Bridge?

I understand that the purpose of a salt bridge is to maintain the neutrality of the solutions in an electrochemical cell, but why do the ions being oxidized and reduced not pass through the salt ...
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52 views

Signs of electrode potentials

Why is the oxidation potential given a positive sign and the reduction potential a negative one? Also, in my book a bunch of formulas are given without any explanation: $E^{o}_{cell}= $ Oxidation ...
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Do the dimensions of the cathode and anode matter in electrochemistry?

I'm curious whether the dimensions of the cathode and anode matter in an electrochemical process. Let's take copper electrorefining as an example. For instance, should the cathode and anode be of the ...
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Working electrode potential greater than reference electrode potential implies oxidation can occur at working electrode - Explanation

I read on the book "Stephen Saddow - Silicon Carbide Biotechnology - A Biocompatible Semiconductor for Advanced Biomedical Devices and Applications" that, when working electrode WE potential is ...
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23 views

Can oxidation peak tell anything about amount of gold deposited in cyclic voltammetry?

In doing an experiment which involved depositing gold nanoparticles by cyclic voltammetry, I was told the amount of gold that has been deposited can be estimated by comparing the size of the reduction ...
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Where does hydrogen evolution occur when aluminium amalgam is placed in water - aluminium or mercury?

Let's say a drop mercury is placed on clean aluminium sheet; mercury amalgam is formed. The solubility of aluminium in mercury and vise versa at room temperature is fairly low. If the entire sheet is ...
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36 views

The equilibrium between zinc and zinc ions

In order for the equilibrium of zinc ions and zinc to be set up, the forward and backward reaction have to occur simultaneously, such that eventually the rate of the forward reaction will be ...
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168 views

N in Nernst Equation [closed]

My teacher told me that in the Nernst equation, N was the number of electrons transferred. For example, $n = 2$ in $\ce{Ni^{2+} + Zn -> Zn^{2+} + Ni}$. However, say all of the coefficients were ...
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34 views

Electrode specification [closed]

What factors go into selecting an appropriate material for an inert electrode for electrolysis? It looks to me like metal oxides or platinum/platinum-coated titanium are the preferred options. ...
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38 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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Where to find information about galvanic deposition of various metals?

I am looking at the process to deposit Cu and Ag onto metallic surfaces using galvanic techniques. Unfortunately this works not as expected. For example I use 2 rods of Cu in a bath of CuSO4 with ...
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2answers
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Effect of salt bridge on Nernst potential

I learned 2 things: A salt bridge is necessary in a galvanic cell so charge does not build up in the halfcells countering the potential difference created by the separate redox pairs. Indeed, this ...
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24 views

Cell Potential of a cell with a reference electrode

In my textbook there is a question asking about the cell potential of a cell that has a reference electrode. It gives me the equation: $\ce {Ag_2CrO_4(s) + 2e^- -> 2Ag(s) + CrO_4^2-(aq)}$ and ...
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52 views

The effect of the voltage at the Downs cell

I referred the Wikipedia and Advance Chemistry by Philip Matthews, for having a much comprehension on the down cell, but there was a opposition while reading the both references. Wikipedia states ...
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82 views

Maximum possible hypochlorite concentration from electrolysis?

For reference, "electrochlorination" is just the electrolysis of a simple solution of water and table salt (NaCl) followed by reintroducing the chlorine gas produced. But, the Wikipedia article on "...
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1answer
144 views

Electrode polarity in fuel cells

I am studying fuel cells right now and I'm confused about the polarity of the two electrodes. In the diagram below, the anode is shown as negative. However, why do $\ce{H+}$ ions move away from the ...
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1answer
99 views

Why is the conjugate of a strong oxidizing agent a weak reducing agent?

I am a grade 12 student. While I was reviewing some electrochemistry, I had the following question. Take this reduction half-reaction: $$\ce{F2 (g) + 2e- <=> 2F- (aq) + $\pu{2.87V}$}$$ I know ...
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33 views

Why are signals broadened in polarography?

In the attached polarogram from Heyvrovsky's 1959 Nobel lecture, transitions from one plateau to the next are smoothened out rather than sharp and abrupt. Why is that? I understand that currents were ...
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2answers
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Would a hydrogen/oxygen fuel cell be a good choice for energy storage and generation in H2 rich atmospheric environments?

So imagine an atmospheric probe sent to enter the atmosphere of a giant gas planet. There would be no need to store hydrogen since a compressor or an inlet with sufficient dynamic pressure would allow ...
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45 views

Hull cell test result

I took Hull Cell test with Watts Bath recently and as you see in the picture there is some problems with the coating layer. Test conditions was: Temperature: 55°C PH: 4.5 Current density: 4.5 a/dm2 ...
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How does a negatively-charged ion behave in the electrical field of biphasic systems

The following is the electrostatic potential plot along the z-axis in a liquid-liquid biphasic system (a ionic-liquid vs water). There are some negatively-charged ions in the positive side of z (z > ...
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171 views

Electroplating diamond grit

I want to do electroplating with diamond grit and make profiling, grinding and cutting disks. (see the attached photos) I want to know the process to make the machine or the company whom is selling ...
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48 views

Galvanic Corrosion in a Galvanic cell

I am doing an individual practical at school, which requires us to investigate the reactivity of metals, using galvanic cells. My initial proposal was to investigate the effectivity of different metal ...
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23 views

Nickel Metal Hydrid battery - Discharge curve unusual

I'm currently working on the Honda Insight cylindrical modules 101V NiMH, trying to recondition and just experimenting with them. Nominal cell voltage = 1.2V I came across a discharge profile that I'...
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34 views

How does cyclic voltammetry in a electrolytic cell measure the precise oxidation potential?

From what I understand, the potential necessary to induce a current to flow in an electrolytic cell depends on both reduction potentials of the anode and cathode reactions, where E(cell) is comprised ...
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1answer
152 views

What does the osmotic pressure do in an electrolytic solution?

I have learnt that in an electrochemical cell, the osmotic pressure in the solution hinders the flow of ions from the electrode to the solution, rather some ions may accumulate on the electrode ...
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88 views

What effect does an increase in concentration of copper sulphate solution have on the rate at which copper is deposited at the cathode?

I have been studying electrolysis in school and was wondering whether a higher amount of copper sulfate solution would produce a greater mass of copper in an electrolytic cell with two copper ...
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1answer
978 views

Does the concentration affect the voltage in electrochemistry

Hello for my final chemistry lab we are doing electrochemistry. For my independent lab I'm using 10mL of ZnSO4 and 10mL of CuSO4. Then connect them with a salt bridge. I connect Zn metal and Cu metal ...
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21 views

What MnO2 and graphite do I need for making a dry cell battery?

I'm playing around with making my own dry-cell battery and I want to make sure I understand the pieces before diving into it. My plan is to make it like a layer cake: zinc sheet, paste of ...
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163 views

What is the purpose of the electrolyte in the half-cell where oxidation is taking place?

In an electrochemical cell that consists of two half-cells, there is an electrolyte and an electrode in each half-cell. Example: $$ \begin{align} \ce{CuSO4(aq) + 2e- &-> Cu(s) + SO4^2-(aq)} \\ ...
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49 views

Is the ionic solution of a half-cell part of the electrode in a electrochemical cell? [closed]

A simple electrochemical cell consists of two half-cells, that is: a metal solid submerged in a solution. Additionally, there is salt bridge connecting the half-cells. Ex: $\ce{Cu(s)}$ in $\ce{CuSO4(...
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26 views

Electron transfer rate equation for Electrodeposition

$$k=\cfrac{mnFv}{RT}$$ where $n$ is the electron transfer number (in my case, 1), $F$ is Faraday's constant, $v$ is my scan rate ($0.1 ~ \mathrm{V/s}$), $R$ is my gas constant, and finally ... $m$! ...
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1answer
74 views

Can I use pure zirconium as an anode in electrolysis?

I read that zirconium is not very reactive even when supplied with a current in an electrolyte. If I had a sizable piece of it, can I use it to perform electrolysis for rust removal of items? Would it ...
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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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33 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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1answer
280 views

In the simplest terms, what is exchange current density?

what is exchange current density, and ideally how does it relate to overpotential I know it's related to the amount of dynamics in a reaction, so it can tell us how simple or complex a reaction ...
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1answer
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In a two electrode system, is the applied current density referring to just the working electrode or to the auxiliary electrode as well?

I'm doing an experiment electrosynthesizing a polymer using a two electrode cell and it says to do it under 0.5 mA/cm^2. However, I am unsure if that means 0.5 mA per square centimeter of surface area ...
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Can a galvanic electrochemical cell produce current only one time without a salt bridge?

I think that galvanic cell produce current only one time without salt bridge. Potentional difference of both the electrodes are different and the electrons flow till their difference becomes same.Salt ...
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1answer
40 views

How come when it rusts iron can undergo oxidation without the prescence of a another metal to undergo reduction?

It seems to me rusting is an electrochemical process where oxygen, which has particularly high electronegativity, fills the role of cathode or is that an incorrect way to put it?
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1answer
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Calculating the EMF of cell

Find the EMF of the following cell : $$\ce{Pb(s)}, \ce{PbSO_4}|\ce{SO_4^{2-}}(\pu{0.100M})||\ce{Pb^{2+}}(\pu{0.004M})|\ce{Pb(s)}$$ Given: $E^0_{\ce{PbSO_4|Pb,SO_4^{2-}}}=\pu{-0.359V}$ and $E^0_{...
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What material electrode is best suited for high current density aqeuous Bromide electrolysis?

I have found that the anodic breakdown potential of Titanium in the presence of Bromide ions is around 1 volt - too low for practical application. Tantalum sounds much more promising when considering ...
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1answer
128 views

Obtaining values for electrical mobility from ion transport numbers in a Hittorf cell

I am following the experiments detailed in the links below in order to find the electrical mobility of a variety of ionic species: Wikipedia article on ion transport numbers and Hittorf method PHYWE ...
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1answer
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Which species are oxidized and reduced when sufficient voltage is applied?

For example, you have two salts in a solution. Say one of the species half reaction requires 1V (standard electrode potential), and another requires 3V, and you have a current running through the ...
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1answer
1k views

Difference between equivalent conductance and equivalent conductivity [closed]

I find questions in my book which ask for the equivalent conductivity and sometimes for the equivalent conductance. And then when I look at the solution, they've used the same formula for both. This ...
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0answers
767 views

How does the cathode of an electrolytic cell drive the anode reaction?

Consider this electrolytic cell: In this cell, electrons from the anode of the battery travel to the cathode of the electrolytic cell, where hydrogen ions are reduced into hydrogen gas. This drives ...
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1answer
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Extraction of metals using electrolysis

I came across a question that goes as: The electrolytic method of reduction is employed for the preparation of metals that are: Less electropositive Moderately electropositive Highly ...