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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2answers
291 views

Disproportionation of silver(I) in aqueous solution

Use the following equations to predict whether or not $\ce{Ag+}$ ions will disproportionate in solution: $$ \begin{align} \ce{Ag+(aq) + e- &-> Ag} &\qquad E^\circ = \pu{+0.80 V}\\ \ce{Ag^2+(...
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2answers
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Proper method to electroplate aluminum?

I'm looking to plate some aluminum with silver using a basic solution. My first attempt was to use sodium carbonate to make silver acetate. I sped up the process using hydrogen peroxide. I used the ...
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1answer
219 views

Is it easier to oxidise iron(II) to iron(III) in acidic or alkaline solution? [closed]

Is it easier to oxidise $\ce{Fe^2+}$ to $\ce{Fe^3+}$ in acidic or alkaline solution? $$ \begin{align} \ce{Fe &-> Fe^2+(aq) -> Fe^3+(aq)}\\ \ce{Fe &-> Fe(OH)2 -> Fe(OH)3} \end{align}...
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1answer
124 views

Cis and trans electrodes

I have come across use of the terms cis and trans electrodes in the context of nanopores and driving charged biomolecules through a pore using an electric field [1]: FIG. 1. Drawing of the cis ...
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1answer
110 views

Expression for Gibb's free energy change for a cell reaction

According to Chemistry Libretexts, the Gibbs free energy change of a cell reaction is related to the cell voltage as $$ \Delta G = -nFE,$$ where $n$ is the number of moles of electrons passed and $F$ ...
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1answer
69 views

Silver “polish” with aluminum foil left a hard yellow coat [closed]

I cleaned my silver teapot with the aluminum foil-baking soda-hot water method. Usually this works well on my silver plated flatware. However, this time it left a hard yellowish coating. I was only ...
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1answer
403 views

Why is cell potential an intensive property? [closed]

I've heard that cell potential is an intensive property. However, we know that an intensive property does not depend on number of moles, mass, or concentration of the substance involved. However, when ...
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1answer
295 views

Writing the overall cell reaction for the Calomel electrode

I an studying about electrochemical cells, and came across the Calomel electrode. It turns out that the half cell reactions and the overall reaction are as follows. Anode half-cell: $\text{Hg}_{2}\...
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1answer
109 views

How could burying a copper and zinc plate underground connected by a surface wire (earth-based Galvanic cell) promote crop growth?

Background: To quote a source: In the 1840s, W. Ross of New York reportedly obtained a severalfold increase in the yield of a field of potatoes when he buried a copper plate (5 ft x 14 ft) in the ...
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1answer
139 views

Convention in electrochemical cell notation

While writing the cell notation for a cell, doesn't one have to write the two states in which a species exists in a sequence appropriate to the reaction in which they participate? For example, in the ...
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0answers
63 views

How can I calculate the diffusion limiting current density?

I know the concentration of a substrate in a water solution and I want to calculate the diffusion limiting current density for an electrode that reacts with that substrate. What are the steps to ...
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1answer
199 views

What is the number of electrons being transferred in electrolysis of aluminum oxide? [closed]

$$\ce{ 2/3 Al2O3 -> 4/3 Al +O2}$$ As we know, to find the Gibbs free energy, we need to use this formula: $$ G= -nFE^\circ$$ What would $n$ be in this case? After breaking it down into the half ...
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1answer
73 views

Why the electrolyte is made up of the same metal which is being electro refined? [closed]

For example for the electrorefining of Cu the electrolyte is CuSO4... WHY the salt of the same metal is used as an ELECTROLYTE..??
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2answers
94 views

Why we do not add salt water to the batteries instead of acid? [closed]

Actually I was just thinking that since we add acid to the batteries to increase the conductivity but the thought simply crossed my mind that salt are strong electrolytes so there should be a good ...
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2answers
592 views

How do ions conduct electricity? [closed]

I mean to ask what do ions actually do while conducting electricity? Do they simply take up the electrons and transport it? If it is so, I do not understand how anions can take up more electrons if ...
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1answer
1k views

Does standard electrode potential depend upon temperature?

Does standard reduction potential depend on temperature? I am confused because my institute gives the definition for standard reduction potential as the potential that is measured at standard state ...
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3answers
150 views

Current with an ionic solution [closed]

For the last assignment of the school year, my science teacher gave the class questions about chem, physics, etc. The third question had me confused and I'll be thankful for all the help given. The ...
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1answer
65 views

Are electrostatic effects temperature dependent? [closed]

A charged particle like an ion, does its repulsive or attractive effect on other particles change with temperature? Are electrostatic effects temperature dependent?
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1answer
134 views

Role of potassium hydroxide in alkaline battery?

Is the role of potassium hydroxide ($\ce{KOH}$) in an alkaline battery to provide hydroxide for the reaction with zinc? Would the battery cease to work if $\ce{KOH}$ was removed and only $\ce{OH-}$ ...
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0answers
29 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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68 views

Reduction potential for reduction of O2 to H2O2 in alkaline medium

I've read that $\ce{H2O2}$ is a good reducing agent in alkaline medium and can reduce $\ce{Fe^3+}$ ions to $\ce{Fe^2+}$ in alkaline conditions. But I need to verify this using the standard reduction ...
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1answer
101 views

Copper brightness change

In an electrolysis situation I have identified a slight brightness change on a copper electrode. What might have happened? I'm dealing with different experiments and this reaction occurs in some of ...
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1answer
217 views

How does the charge imbalance affect the cell reaction when there is no salt bridge in a galvanic cell?

As mentioned in the answers to this question Why is it important to use a salt bridge in a voltaic cell? Can a wire be used? a salt bridge is used to keep the two half cells neutral. i understand how ...
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34 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
291 views

Rusting of iron is quicker in saline water than in ordinary water [duplicate]

I feel so because, saline water has more more electrons and because of that there will be oxidation will take place faster and hence the overall process will speed up. Is this explanation good enough ...
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1answer
119 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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2answers
788 views

How does overvoltage affect the products of electrolysis?

When you electrolyse an aqueous solution of $\ce{NaCl},$ the product formed at cathode is $\ce{H2}$ gas (preferential discharging), but the product formed at anode is $\ce{Cl2}$ gas. According to ...
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0answers
93 views

What happens to a flat lemon and can it be recharged? [closed]

A lemon can be used as a battery, and is often used to teach kids the basics about electricity and chemistry. This is due to their acidic and electrolytic properties. What happens to a lemon when it ...
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110 views

Aluminum Hydroxide electrolysis

Does molten Aluminum Hydroxide break up to aluminum, water, and oxygen by electrolysis? It's easy to write the equation $$\ce{4Al(OH)3 -> 4Al + 6H2O + O2}$$ but is this actually possible?
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1answer
97 views

In a battery, what happens to LiCoO2 when the lithium leaves? It becomes CoO2?

What chemical compound exists at the cathode of a lithium-ion battery when the lithium is not there? The cathode is usually described as $\ce{LiCoO2}$, so does it become $\ce{CoO2}$? $\ce{CoO2}$ ...
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1answer
734 views

Electrolytic Refining of Silver Nitrate

I read that the electrolytic refining of Silver is done using dilute silver nitrate as an electrolyte and a small percentage of free $\ce{HNO3}$. The following reactions are possible at the anode: $$\...
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1answer
140 views

How does electrolytic conductance depend on solvation?

My textbook says: If the ions are strongly solvated their effective size will increase and hence their conductance will decrease P.s after reading my textbook, I don't think I'm sure what solvation ...
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1answer
400 views

What is the state of aggregation of iodine formed during electrolysis of molten nickel(II) iodide? [closed]

Assume the electrolysis of molten $\ce{NiI2(l)}$ (inert electrodes) in a cell. The cell with a heating element is in the room; the room is at $\pu{25 °C}$ and $\pu{101.3 kPa}.$ The half-reaction for ...
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1answer
136 views

Aluminium, Carbon, Aluminium Sulphate battery. What's the reaction?

I made galvanic cells from the following items (while trying to do something else), and they give between 0.6 V and 1 V per cell. Aluminium foil – negative terminal Carbon (these work: charcoal ...
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1answer
226 views

Calculating the biological standard potential

I have an electrochemical cell with following overall reaction: $$\ce{5 Sn^4+ + 2 Mn^2+ + 8 H2O <=> 5 Sn^2+ + 2 MnO4- + 16 H+}$$ I have defined the half reactions as: $$ \begin{align} \ce{Sn^...
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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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1answer
184 views

Why is it necessary to bubble hydrogen through the electrolyte in a hydrogen electrode? [closed]

I searched from the internet but i got confused. I was not sure about my answer.
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1answer
51 views

Where do the electrons in lead–acid battery come from? [closed]

$$ \begin{align} \ce{PbO2 + H2SO4 &-> PbSO4 + H2O + O} &\quad &\text{(anode)}\\ \ce{Pb + H2SO4 &-> PbSO4 + H2} &\quad &\text{(cathode)} \end{align} $$ The cathode’s $\ce{...
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31 views

Mass Transport and Ion Transport - Li-ion Batteries

I am new to the field and trying to grasp the theories/ physical phenomena behind the Li-ion batteries. I came across two phenomenons 'Mass transport' and 'Ion transport'. As I understood Mass ...
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1answer
63 views

Contradiction in variation of conductance and conductivity on dilution

I do conceptually understand that on dilution conductivity decreases and conductance increases but if we look at the formula of conductivity, a contradiction seems to arise. $$\kappa=GG^*$$ where $\...
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0answers
161 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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1answer
62 views

Why can't two 3° free radicals combine?

In Kolbe Electrolysis, my teacher told that when a 1° or 2° free radical is used, we get alkanes through dimerisation. Why wont dimerisation occur for a 3° one??
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1answer
454 views

Why does molar conductivity depend on the volume of the solution? [closed]

I have been searching the answer to this question everywhere and (almost) the only answer I get is to formula based: ‘Since molar conductivity = k / M = k/1/V for one mole = kV Therefore molar ...
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0answers
96 views

Did both temperature of nernst equation same

I saw the nernst equation I have a doubt.Did the temparature at which Standard potential is measured is also the temparature at which electrode potential is measured. I mean Did the temperature (T) in ...
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3answers
147 views

Trying to understand the chemistry in an iron carbon battery

I am trying to understand the chemistry that occurs in an iron carbon battery during charging. The negative electrode is iron, the positive electrode is carbon. The electrolyte is iron(II) chloride. ...
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4answers
1k views

In NaCl electrolysis, why does chlorine ion get oxidized but not oxygen ion? [closed]

In $\ce{NaCl}$ electrolysis, on the positive electrode (aka. on the electrode where oxidation happens), $\ce{Cl-}$ ions are oxidized to $\ce{Cl2}$. But why don't we see any $\ce{O^2-}$ (naturally ...
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1answer
181 views

Calculation of the cell potential of a lemon battery experiment

I have the following problem that I would like to get checked. I’m told to calculate the cell potential of a simple lemon battery experiment. After Finding out the oxidizing agents and the reducing ...
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1answer
440 views

why does galvanic cell stop working when charge neutrality is not maintained? [closed]

In galvanic cell, salt bridge maintains charge balance between solutions. If there's no salt bridge, charge neutrality will be broken as solution(anode) becomes positive and that of cathode becomes ...
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4answers
709 views

What happens when a piece of copper is placed in 1M HCl?

I know that the answer is that nothing happens, but the explanation is confusing me in some places. Firstly, we are given that: \begin{align} \ce{Cl2 + 2e- &-> 2Cl-} & (E &= \pu{1.36 V})...
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1answer
198 views

What is the substance turning salty water green when electrolysed? [duplicate]

I am a student and I take O.L. Chemistry, in my knowledge I know if I electrolysed concentrated aqueous NaCl solution I should get Hydrogen evolved at the cathode and chlorine at the anode. I did an ...

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