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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What is the relationship between migration and the potential of double layer theory?

Double layer theories like that of Gouy-Chapman give the electrostatic potential $\ \phi\ $ in solution. For a symmetrical electrolyte and small potential drops $\ ...
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23 views

Activity Coefficients from Electrode Potentials

Lets say we want the activity coefficient of $\ce{Cu^{2+}}$ ions in solution. Would we simply setup one half cell of a $\ce{Cu}$ electrode in a known concentration of $\ce{CuSO4}$ and then connect ...
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16 views

Calculating molar conductance?

Ok, so the following question is given in my text book. Of the molar conductance value of $Ca^{2+}$ and $Cl^-$ at infinite dilution are respectively $118.88\times10^{-4}$ and $77.33\times10^{-4}$ ...
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27 views

how to determine the relative differences in activity between metals

I am doing a lab for school and I do not know what this question is asking. In this lab we are making electrochemical cells from different metals.
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69 views

Electrochemical half cell without redox couple

In a book about electrochemistry the situation of a cell is described of which one half cell has an "undefined thermodynamic potential" as no redox couple exists: $$ Pt/Cu^{2+}\ (0.01\ M),\ Cd^{2+}\ ...
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1answer
59 views

Deriving goldman equation

So I've been trying to follow the derivation of the Goldman-Hodgkin-Katz equation on Wikipedia (https://en.wikipedia.org/w/index.php?title=Goldman_equation ) - I can follow it through after it sets up ...
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40 views

Discrepancy in current inside an electrolytic cell

Suppose A(+)B(-) type fused salt is present in an electrolytic cell (not electrochemical cell). Let n electrons be entering the cell per second. Since each A(+) requires one electron to discharge, so ...
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1answer
50 views

Electrochemistry Question from USNCO

Given these standard reduction potentials, what is the standard reduction potential for $$ \ce{Co^{3+}(aq) +3e- -> Co(s)} $$ Given: $$ \ce{Co^{3+}(aq) + e- -> Co^{2+}(aq)} \ \ \ E°=1.82 V ...
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119 views

Why do electrons follow from Zn to Cu but not Cu to Zn in the lemon battery experiment?

In the lemon battery experiment, as I understand, both $\ce{Zn}$ and $\ce{Cu}$ meet acid in the lemon, cause $\ce{Zn}$ and $\ce{Cu}$ release electrons to form $\ce{Zn^{2+}}$ and $\ce{Cu^{2+}}$. So ...
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28 views

Electrochemistry lye quality

With the following setup: plastic container, water (impure), pencil (anode), tin foil (aluminum, cathode) and solar panels supplying electrical charge (roughly 36v at about 400-800ma), with the ...
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1answer
23 views

Electrolytic cell chemical composition during/after charging?

I have a pot with some (bottled) water and added (sea) salt. It has a pencil (graphite) and tin foil (aluminum). The pencil is connected to the positive outlet of a solar panel and the tinfoil is ...
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1answer
85 views

Half cells: difference between E(cell) = E(cathode}-E(anode) & E(cell) = E(oxidation) + E(reduction)

When do I use each of the above? If I use one or the other they give me difference results. For example, I'm trying to put the Volts into an equation to find standard free energy change. $$\Delta ...
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4answers
130 views

How could I create a machine that as rapidly as possible creates greenhouse gases from air?

For a very large-scale project, I am trying to create a greenhouse gas demonstration device, which rapidly produces greenhouse gases from atmospheric air using only electricity, or any chemical ...
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1answer
39 views

How do I work out the amount of H+ ions in a sodium hydroxide and water solution?

I know the $pH$, pressure, temperature and concentration of the solution. Is there a method I can use to work out the amount of $\ce{H+}$ ions?
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1answer
57 views

How do I derive the Nernst equation in the case in which R is absent?

Does anyone know what the intermediate calculations are to obtain equation 1.4.14? Taken from Fundamentals and Applications (Bard) page 31 To be more precise, how to obtain (1.4.14) from ...
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1answer
64 views

What is made at the copper cathode when electrolyzing water?

I just electrolyzed water with $\ce{NaHSO4 -> HSO4- <=> H+ + SO4^2-}$ with copper electrodes. At the anode this reaction happened: $\ce{Cu -> Cu^2+ + 2e-} \hspace{26 mm} E_0 = -0.34V$ ...
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44 views

Does anyone know where I can find the reaction rate coefficient and design equation for the electrolysis of brine and sodium hydroxide solution?

equation 1) $\ce{2 Cl^{–} -> Cl_2 + 2e^{-}}$ equation 2) $\ce{2 H2O + 2 e^{–} -> H2 + 2OH^{–}}$ These equations are the key reactions in the chlor-alkali process. I want to model a reactor ...
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46 views

What's the voltage of a battery?

The definition of voltage I'm familiar with is the amount of electric potential energy per unit charge at a location. My prof defined the voltage of a battery to be the amount of potential energy ...
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70 views

Variable oxidation state of transition metal ions

Transition metals can form stable ions with different oxidation states. But I am confused why doesn't only the most stable state exist. Let me clarify my question more: $$\ce{Ti^{2+} -> Ti^{3+} + ...
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1answer
96 views

How to design an electrochemical reactor for the production of chlorine and hydrogen? [closed]

For my university design project, I have to design an electrochemical reactor to electrolyse brine and sodium hydroxide solution to produce hydrogen and chlorine. I have the chemical equations and ...
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1answer
52 views

Why don't B, C, Si, have ionic forms?

Also, why can some elements such as Fe have different ionic forms such as Fe2+ and Fe3+? What determines each form?
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40 views

Salinic bridges in voltaic cells

I'm doing a study a study on voltaic cells. I've been working with them for a while and one of the questions that I've had is how does the salt bridge affect the cell. I mean, I know it allows ions to ...
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1answer
69 views

What happens to the hydroxide anion during the electroreduction of water?

The reduction of water at a cathode is represented by the following equation: Cathode (reduction): $\ce{2 H2O_{(l)} + 2e^{−} → H2_{(g)} + 2 OH^{-}_{(aq)}}$ If this is done in a divided cell, what ...
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1answer
40 views

What prevents the anode from corroding in electrolytic organic reactions?

An electrode can be plated by having a solution full of electrolyte, using the the metal that will receive the plating as the cathode, and the metal doing the plating as the anode. Current is put ...
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42 views

I want to make electricity of aluminiun cans i.e. reverse the process of refinning aluminium. Any ideas?

Recycling Al cans to produce electricity,i.e. to reverse the process of electrolysis and produce electricity
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1answer
60 views

Electrochemistry Question: reaction potentials versus current density?

In many electrochemistry scholarly articles/studies they talk about certain specific reactions occurring at certain voltage potentials, while in other articles they talk about current density as the ...
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3answers
75 views

Alternatives to Ring Stands

I'm trying to find an alternative to simple ring stands to hold a simple electrochemical cell. The issue is that it is difficult to adjust the height to the right position to within even a couple ...
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1answer
58 views

Intuitive understanding of standard electrode potential

I have read many books on standard electrode potential and they define the term in various ways but I just can't seem to get an intuitive idea of it... $Cu^2+ 2e^- \longrightarrow Cu$ Standard ...
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2answers
90 views

Balanced reactions at the anode and cathode [closed]

A current of 2.25 A is applied to $\ce{NiCl2}$ solution A. Write the balanced half reaction that takes place at the anode B. Write the balanced half reaction that takes place at the cathode Can ...
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1answer
46 views

Similarity between Ecell and equilibrium constant Kc

$$\ce{Cu^{2+} + Zn<=>Zn^{2+} + Cu}$$ $K_c=1.9*10^{37}$ $E_{cell}=1.1V$ I know that they both suggest that the forward reaction is going to completion but can someone please tell me a bit ...
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1answer
45 views

Intuition for electrode potential

If I connect a zinc half cell (Left hand side) and a copper half cell (right hand side), I get an E cell value of 1.1V taken from the voltmeter. If I replace the voltmeter with a light bulb, I will ...
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88 views

Why can we disregard stoichiometric coefficients when computing reduction potentials?

Example: A $Cd // Cr$ Galvanic cell has redox half reactions: $\ce{Cd^{2+} + 2e^- -> Cd}$ $E_{cell}$ = -0.4 $\ce{Cr^{3+} + 3e- -> Cr}$ $E_{cell}$ = -0.7 Balanced equation of reaction ...
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199 views

Can an aqueous solution conduct electricity forever?

We know that pure water does not conduct electricity, but salt water is a decent conductor. This is commonly explained by saying that "the ions carry the current through the solution", an explanation ...
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107 views

Can bromide ion reduce ferric ion?

Can bromide ion reduce ferric ion ? Just a query. In my opinion it can since bromide ion can undergo oxidation. Is my answer correct?
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1answer
192 views

“Number of moles of electrons involved in the reaction” for hydrogen cell

I understand we can calculate the maximum work done by the electromotive force (driving electrons through a cell) by multiplying the potential of the cell with the charge of one mole of electrons ...
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2answers
72 views

Why is current non-zero when applied potential is still below E$^0$ in cyclic voltammetry?

In this diagram (Evans et al., J. Chem. Edu.) the current is non-zero, but the potential is still below the normal potential. How can the compound become oxidized at the working electrode, when the ...
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1answer
150 views

how is the relation between Gibbs free energy and cell potential?

First of all what is exactly Gibbs free energy in regards to an electrochemical process? How can we visualise it? How does Gibbs free energy change in an electrochemical reaction? How is it related to ...
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3answers
180 views

why does znso4 aqueous solution when boiled with solid zinc and solid copper cause zinc metal to be deposited on copper?

I did an experiment where I dissolved 30 grams of zinc sulfate in water and boiled it with strips of solid zinc metal and strips of copper metal and a layer of zinc was deposited on the copper. I ...
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68 views

How can normal potentials be explained?

For example (for reductions) $$ \ce{2e-} + \ce{Cd^{2+}} \rightarrow \ce{Cd}:\mbox{ } E^0 = -0.403 V\\ \ce{2e-} + \ce{Ni^{2+}} \rightarrow \ce{Ni}:\mbox{ } E^0 = -0.25 V $$ How can I rationalize this ...
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2answers
137 views

How much electricity could be generated by a person's stomach acid?

Motorola has a device that is powered by stomach acid. Given that a battery consumes the electrolyte as it generates a charge, how much power could be generated using a device such as this? Let's ...
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1answer
68 views

Silver electrorefining

Ok, so let's say I have raw silver which is polluted with a bit of gold, copper and lead. So through electrorefining I want to make pure silver out of it. Let's say I have it all in an acidic ...
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17 views

surface sensitive techniques

is there a way to analyze the surface of a transition metal (chemical composition and possibly oxidation states) immersed in a molten KOH environment, while the metal is also under electrochemical ...
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2answers
938 views

Derivation of relationship between Gibbs free energy and electrochemical cell potential

Why is $\Delta G=-nFE?$ I don't understand what the motivation is behind this definition. Was it derived or just given? The textbook provides no justification for this equation. In fact, much of ...
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1answer
1k views

How do I calculate the cell voltage using the following half-reactions and solubility products?

$$\ce{Cu_{(s)}|CuI_{(s)}|I^{–}_{(aq)}||Cl^{–}_{(aq)}| AgCl_{(s)}|Ag_{(s)}}$$ The concentrations of $\ce{NaCl}$ and $\ce{KI}$ are at $0.120 M$ and $0.090 M$, respectively, in the following ...
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87 views

Why is CuSO4 used as electrolyte while purifying copper?

During the electrolytic purification of copper, the electrolyte is taken as copper(II) sulphate ($\ce{CuSO_4}$). Is there any particular reason for this? Could another salt of copper, say ...
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138 views

Why do they use graphite anodes in the Hall-Heroult process?

In the Hall-Heroult process of extracting aluminium from aluminium oxide, the electrolyte is a liquid mixture of cryolite ($\ce{NaAlF_6}$) and aluminium oxide (of course). The cathodes and the anodes ...
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49 views

During electrolysis, why are the products attracted to the cathode?

Take the electrolysis of Lead(II) bromide: We can write it as two half-reactions: $$\ce{Pb^{2+}(l) + 2e^{-} \rightarrow Pb(l)}$$ $$\ce{Br^{-} \rightarrow Br + e^{-}}$$ In the electrolysis ...
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1answer
371 views

Vertical lines in a Pourbaix Diagram

I know that because of the absence of the hydrogen ions in a reaction ($n_{H+} = 0 $) , the correspondent E-ph line have to be horizental , but what exactly the types of reactions (if there is) that ...
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1answer
572 views

What is the role of hydrochloric acid in a copper electroplating bath?

Considering water as a given, the third most important ingredient in a copper electroplating solution, as a short survey of related recipe webpages will show you, is hydrochloric acid (HCl). Here's a ...
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41 views

Corrosion Prevention Technique

What are the advanced corrosion prevention techniques that can be used for IBR boiler? I have recently seen a technique which involves magnetic waves. It was something like this. In that technique ...