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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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4
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1answer
451 views

Reduce chlorine gas

I have a simple electrolysis setup which uses aqueous sodium chloride as electrolyte. The problem is that, the setup makes tons of chlorine gas along with hydrogen (I only want hydrogen). I didn't ...
3
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1answer
2k views

What are possible side reactions for the generation of hydrogen via electrolysis?

I recently completed making a simple water electrolysis setup to generate hydrogen which uses two graphite rods from a standard AA battery. The power source is a $24~\mathrm{V}$ $6~\mathrm{A}$ adapter....
2
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1answer
873 views

Corrosion of metals and observations in the agar medium?

I want to know which metals oxidize and which is reduced and changes in medium and observations? According to my knowledge more corrosion will take place in Zn and Fe also corrode. Then copper should ...
4
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1answer
198 views

What can we say about the Gibbs free energy if it decreases or not?

[Sorry if the question looks trivial but I have thought about it for days and red a number of books all with no success.] In almost every thermodynamics book that has something to say about chemical ...
0
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1answer
186 views

Liquid crystal current flow

In a liquid crystal cell used for LCD the conductive substrates, usually made of ITO, are in contact with the liquid crystal. The question is: when a voltage is applied to the electrodes to reorient ...
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1answer
7k 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 $\ce{CuCl_2}$...
4
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1answer
820 views

In a galvanic cell, why does an electrode with a higher potential “pull” the electrons from the electrode with a lower potential?

I'm doing Grade 12 Chemistry and I'm unsure of this, taking the hydrogen electorde as having a potential of 0 volts. I'll use the copper-zinc cell as an example. Just let me know if I've got the full ...
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0answers
45 views

Relating Thermodynamic & Transport Properties to Electrochemical discharge curve

What are the fundamental thermodynamic & transport properties that the discharge cycle of a rechargeable battery with an intercalating cathode (like Li-ion) should depend upon? The few that I ...
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2answers
258 views

Are homemade batteries a practical alternative during a blackout?

If your home lost power without warning; are homemade batteries (such as the lemon/potato variety described in this question Are homemade batteries economically practical?) a practical alternative for ...
2
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2answers
1k views

How does a simple alkaline battery work?

The basic + - electrolyte set up. Modern batteries and the like. How exactly do they work?
7
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1answer
1k 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 ...
2
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1answer
76 views

Confusion regarding specific conductivity [closed]

Is there any difference between the terms specific conductivity and conductance. If yes, please explain.
9
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2answers
633 views

Why do acids favor the oxidizer? And bases the reducer?

Simply put, why does adding acid to the cathode up the cell voltage? From what I understand, acids are proton donors. Do these positive protons attract electrons toward the cathode compartment of the ...
1
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1answer
141 views

Kinetic validity; redox reactions

What's the kinetic validity of the following way of balancing the above redox reaction? I've done some searching of the literature; I've never come across oxide anions being mentioned in redox ...
6
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1answer
17k views

Why is the water reduction of oxygen favored in acidic conditions?

The standard reduction potential of diatomic oxygen in acidic conditions is +1.23 volts. However, the standard reduction potential of diatomic oxygen in basic conditions is only +0.40 volts. Why is ...
2
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1answer
2k views

Reduction potential and electron affinity

Why is it that fluorine has a much greater reduction potential than chlorine, despite the fact fluorine has a lower electron affinity than chlorine? I understand that fluorine has a lower electron ...
2
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1answer
258 views

Calculating Redox Potential; Coupled Reactions

For the reaction of silver and hydrochloric acid to form silver chloride: would the following be the correct way to couple the below two half reactions? $\ce{2Ag(s) + 2Cl^- ->2AgCl(s) + 2e^-} ~~E^...
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1answer
174 views

Electrolysis of Strongly Basic Water

What happens when strongly basic water is electrolyzed? I know that the electrolysis of water in strongly acidic solution involves hydrogen protons; will these protons still be involved in strongly ...
3
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1answer
93 views

Since aqueous acids release Hydrogen cations into the solution, will an electric current create Hydrogen gas?

I was wondering that since acids dissociate in water to make a lot of $\ce{H+}$ cations. Is it possible that introducing a supply of electrons via an electric current, would create $\ce{H2}$ gas?
1
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1answer
235 views

Conjugate Theory and Redox

I'm trying to apply conjugate theory, which I can apply very well to acids/bases, to redox. Can you verify my logic, which I have broken down below? 1) I know that solid sodium is a strong reducer. ...
5
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1answer
922 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
506 views

What does the slope of a Levich plot represent?

I know that the limiting current is proportional to the square root of the rotation speed, but what does the slope of the plot represent?
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2answers
257 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 ...
2
votes
1answer
323 views

Voltaic and electrolytic cells

Why more attractive metals will be oxidized? Aren't they being reduced, because they attract and receive electrons from negative polyatomic ions? So they will be anodes, where oxidization occurs. Why ...
2
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1answer
4k views

Gas Electrode Working

How does a SHE electrode work? Does the $H_2$ gas get absorbed on the platinum electrode? How is it reduced? How are electrons transferred from the adsorbed gas to the solution? How is $H^+$ ...
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1answer
4k views

Electrolysis of aqueous lead nitrate

When going through one of my chemistry textbooks, I saw that the electrolysis of aqueous lead nitrate led to oxygen being formed at the anode and lead being formed at the cathode. However, in school, ...
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0answers
123 views

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 $\ \phi\left(x=0\right)-\phi\left(x\...
8
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1answer
279 views

Difference between non-thermal and thermal ionized gases

Why or when does non-thermal plasma become thermal? How do we know before hand if the ion temperature will differ from the electron temperature, on what parameters does it depend - where is the ...
4
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1answer
780 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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0answers
124 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 ...
2
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0answers
50 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 ...
2
votes
1answer
95 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 ...
4
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2answers
10k 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 ...
5
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1answer
1k 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 $\frac{...
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1answer
258 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: $\ce{Cu -> Cu^2+ + 2e-} \hspace{26 mm} E_0 = -0.34V$ ...
2
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1answer
7k 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 ...
3
votes
1answer
108 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 ...
3
votes
1answer
78 views

Electrochemical characterization of benzenesulfonamide

I'm trying to elucidate current peaks for benzenesulfonamide, using an acetic acid-sodium acetate 0.1M buffer at pH 5.5 as electrolyte. When doing cyclic voltammetry, I get a voltammogram similar to ...
2
votes
1answer
181 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 ...
5
votes
2answers
843 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 ...
1
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1answer
960 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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2answers
3k 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 ...
2
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2answers
1k 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?
0
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1answer
5k 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 ...
3
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1answer
130 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 ...
2
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1answer
3k 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 (...
3
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2answers
585 views

What are high throw solutions?

I am trying to make a copper sulfate electroplating solution. I came across a document (Schlesinger and Paunovic 2011) which mentions the amount of copper sulfate that should be added to water to ...
2
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1answer
339 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 reaction,...
3
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1answer
3k 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 ...