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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30 views

Can CO2 Be Electrochemically Reduced to Carbon Nanotubes?

Mitigation of CO2 as greenhouse gas has driven increasing investigation of its chemical reduction. The 2018 paper "Recent Progress in the Theoretical Investigation of Electrocatalytic Reduction of CO2"...
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832 views

Adding Standard Reduction Potentials

I am working the following USNCO problem (#41 from 2002). Based on this question and answer Deriving a reduction potential from two other reduction potentials, it seems that $\Delta G$ must be ...
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How to determine the potential of a cadmium zinc cell under standard conditions?

I write the half-equations: \begin{align} \ce{Zn &<=> Zn^2+ + 2e^-}& E^\circ &= +0.763~\pu{V}\\ \ce{Cd^2+ + 2e- &<=> Cd}& E^\circ &= +0.403~\pu{V} \end{align} In ...
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3k views

Why does the Co³⁺/Co²⁺ couple have such a high reduction potential?

Cobalt is changing from $\mathrm{(3d)^6}$ to $\mathrm{(3d)^7}$ electronic configuration. What's so stabilizing about that? Just by reduction potentials this couple is more oxidising than hydrogen ...
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1answer
45 views

Cobalt electroplating over nickel-plated steel

From my research, I understand that cobalt can be used on top of a nickel layer to improve durability of the nickel plating on a steel object. I am using a nickel anode and nickel acetate as ...
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46k views

Does concentration of salt increase or decrease rate of rusting?

I want to know whether increasing the concentration of salt, specifically $\ce{NaCl}$, increases or decreases the rate of rusting. There are conflicting theories that explain opposite outcomes: ...
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18 views

Solutions when Electroplating

I'm essentially conducting an experiment to see whether using different copper-based compounds when electroplating copper onto an iron nail would give different results. So far, I've used copper ...
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123 views

Why does chromium metal not react with a solution of Mg^2+ even though their standard cell potentials produce a net positive voltages?

Write net equations for the spontaneous redox reactions that occur during the following or NONE if there is no extensive reaction. Use the lowest possible coefficients. Include states-of-matter under ...
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4k views

Calculating Solubility Product of AgCl from electrode potential

I have to use a measured electrode potential to find the solubility product of $\ce{AgCl}$. In our experiment, we first mixed one drop of $\pu{1.0 M}$ $\ce{AgNO3}$ with $\pu{10 mL}$ of $\pu{1.0 M}$ $\...
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How to calculate the cell potential after the reaction has operated long enough for the Fe2+ to have changed by some concentration?

Consider the cell described below at $\pu{261 K}$: $$\ce{Fe | Fe^2+ (\pu{0.925 M}) || Cd^2+ (\pu{0.981 M}) | Cd}$$ Given $E^\circ_\ce{Cd^2+ -> Cd} = \pu{-0.403 V}$, $E^\circ_\ce{Fe^2+ -&...
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Is the 'n' in Delta G = -nFE, ever negative?

Is it possible for $n$ in $\Delta G=-nFE$ to ever be negative? Trying to figure out where I went wrong on some thing and want to rule that out.
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118 views

Difference between electrode potential and standard electrode potential

I was studying electrochemistry but the thing that confused me was that what is the basic difference between electrode potential and standard electrode potential?
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85 views

Is basic solution an electrode?

Question: Calculate the potential of hydrogen electrode in contact with a solution of pH 10. My attempt: Cell reaction: $\ce{ H^+ + e^- -> \frac{1}{2}H_2 }$ I've attempted to solve this ...
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79 views

Determination of solubility equilibrium using galvanic cell reactions

This is the problem: We can determine the solubility equilibrium for silver bromide using cell: Ag (s) | AgNO3 (aq) || KBr (aq) | AgBr (s) | Ag (s) We know that: $\text{AgBr} + \text{e}^- \...
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179 views

How to use Kohlrausch's law with ionic equivalent conductances? [closed]

My text says that for an ionic compound like AxByif ionic equivalent conductance of Ay+ is a and that of Bx- ion is b, then the equivalent conductance for AxBy would be a/y + b/x Now my question is:...
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1answer
63 views

Do the salt bridge ions have to match the ions in the half-cells solutions?

Does the salt bridge in a galvanic cell have to have the same ions as the ones in the solutions? E.g. does it need to have nitrate ions if the half-cells contain copper nitrate and zinc nitrate, or ...
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1answer
33 views

Measuring bioanode potential against Ag/AgCl reference electrode

I'm trying to make a bioanode for use in a microbial fuel cell. I have a piece of carbon cloth in an acetate solution with river sediment. I'd like to know the potential of the anode, so I connected ...
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54 views

Why do reference electrodes have porous frits or membranes as a salt bridge?

From what I understand, they act as a salt bridge between the reference electrode electrolyte and the analyte solution (in a potentiometric titration). But why do we use partially permeable membranes ...
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2answers
91 views

Is it possible to build a non-degrading battery?

I am not a chemist, nor do I know anything about chemistry. What I am interested in are batteries. I don't really care about the whole "Charge in minutes, last for days" types of batteries (the ...
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Instead of using an Ag/AgCl electrode, can I simply use another beaker and connect it to my solution via a salt bridge? [closed]

I'm trying to perform a potentiometric titration as part of my high school laboratory work, by reducing iron(III) to iron(II), and measuring the voltage change as I add cobalt(II) (to reduce it). The ...
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1answer
79 views

Electrosynthesis of HCl? [closed]

I was attempting to synthesize hydrochloric acid and it seems to have formed another form of chlorinated acid. The smell is more of chlorine and is extremely powerful. I got some on my jeans and it ...
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1answer
79 views

Why does electron flow from anode? [closed]

The above is a picture of Galvanic cell. Zinc anode is placed in Zinc sulfate solution so we have ions as Zn2+ and SO42-. On the cathode side we have the same situation we have Cu2+ and SO42-. My ...
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159 views

How does a change in the surface area of the electrodes affect the voltage produced by a galvanic cell?

I did a lab where I increased the surface area of the electrodes in a galvanic cell, that resulted in an increase in voltage. However, I have been reading and that is not supposed to happen. I am a ...
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35 views

Theoretical Calculations for Potential Generated in Salt Water Battery

I am using a $\pu{1.5 M}~\ce{KCl}$ solution as electrolyte and copper and aluminium electrodes but no salt bridge. So basically there is only one beaker with the two electrodes in it with the $\pu{1.5 ...
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Cause of imaginary part of Warburg element in EIS

In electrochemical impedance spectroscopy experiments (EIS) the diffusion of electroactive species at flat, macroscopic electrodes is commonly described by the Warburg element with the impedance ...
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1answer
37 views

Which reactions occur during the oxidation and dissolution of bromide/bromine?

I'm trying to understand the fate of bromide anions during and after they undergo anodic oxidation. I have a solution of 94% DMF/6% water (by volume) with 0.1 M tetrabutylammonium bromide (TBAB) as ...
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Existence of single ion activities

I have used Davies equation to find what I believed was single ion activities and multiplied them on concentrations to define the thermodynamic dissociation constants for any kind of buffer to find ...
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1answer
8k views

How would using different salts in a salt bridge effect the voltage generated by a voltaic cell?

If I use a range of different nitrate solutions (e.g. calcium nitrate, iron nitrate) for the salt bridge in a voltaic cell, what effect would it have on the flow of ions in the voltaic cells? Will ...
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Is it true that “Voigt Circuit” would be able to be fitted to various electrochemical impedance spectra?

"Voigt Circuit" which is a series combination of Voigt elements (i.e. parallel RC's), is commonly used for Kramers-Kronig relations checking; and as I imagine it is generally believed to be able to be ...
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2answers
63 views

What happens if I draw too much current from a home made battery?

If I try to make a battery like one of these: https://www.wikihow.com/Make-a-Homemade-Battery And then I short the two terminals, what will happen? Disregarding anything getting hot and burning up, I'...
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3answers
10k views

What is the freezing point of sulfuric battery acid?

As we all know, the freezing point of absolute sulfuric acid is 10 °C. The average lead-acid battery (sulfuric) uses ~30% sulfuric acid, and has a freezing point much lower than 10 °C. What ...
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3answers
809 views

Why does a complete discharge destroy a Li-Ion-Battery?

I read that completely discharging a Lithium Ion Battery is a very bad idea because it will lose plenty of capacity. But why? I know that the reaction (fot the LiFePO4 battery) is: $$ \ce{LiFePO4 + ...
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24 views

Is the Gibbs energy of bulk metals in a Daniell cell affected by temperature? [closed]

From literature values, it is implied that the change in Gibbs energy of a Cu-Zn voltaic cell is largely due to the difference in Gibbs energy of the bulk metals (solid Cu and solid Zn). Does ...
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1answer
34 views

Is the equation below for Gibbs energy only applicable under standard conditions?

This is quite confusing to me because it seems as if a lot of people use standard state equations and non standard state ones interchangeably: $$ΔG^\circ = -nFE^\circ$$
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118 views

Degradation of anode in electrolysis

In my electrolysis experiment, I used a 9 volt battery, 1:100 mL baking soda:distilled water, and stainless steel electrodes. I noticed that the anode degraded faster than the cathode. Out of ...
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1answer
36 views

Which etching process is better, photochemical or electrochemical?

My boss and I are experimenting with several different ways to micro machine .01" and .005" stainless steel. When I look up how it's done professionally, I see an overwhelming majority of companies ...
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Is electrolysis with AC current possible? [duplicate]

Optimizing everything else, would efficient electrolysis be possible with AC current? Most sources suggest to use DC, but can the water still be split/disassociated with AC?
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48 views

what is the exact meaning of oxidation state? [duplicate]

can you mention the concept of oxidation state without its simple definition i-e it is the apparent charge +ve or -ve.....😪 I found these in wikipedia but didn't understand."Conceptually, the ...
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why do I get chlorine gas production during electroetching?

I was electroetching stainless steel plates with table salt as electrolyte and the power supply was providing 5V, 6A when I placed the anode and cathode about .25 inches apart. I started smelling a ...
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25 views

Changing the CO2 concentration (adding or subtracting) inside a sealed vessel?

I am looking for a method of modifying the CO2 concentration inside a sealed container that is both precise and repeatable (C02 needs adjustment every time the container is sealed, also need to be ...
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36 views

Is it possible to convert a combustion reaction directly into an electrochemical one?

I'm fairly inexperienced in chemistry so forgive me if this question is silly but, why is it not possible to convert a combustion reaction to an electrochemical one directly and harvest the electrical ...
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1answer
2k views

Positive electrode potential of copper

My book (NCERT India) says that the electrode potential of metals is decided by the following factors: Enthalpy of atomisation Ionisation enthalpy Hydration enthalpy It says that the first two ...
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1answer
135 views

In the Nernst equation, does T refer to the temperature of the standard cell or the cell under non-standard conditions?

I am doing an experiment where I am varying the temperature of the electrolyte of the anode half cell. I am trying to calculate the cell potential using the Nernst equation under standard conditions ...
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1answer
84 views

Why is concentration of nickel nitrate constant? [closed]

Consider a cell with both nickel electrodes and a solution of nickel nitrate ($\ce{Ni(NO3)2}$). Current is passed through the solution. The $ E° $ values predict that nitrate in the solution should ...
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1answer
72 views

Working principle of simple chemical cells

I have just learnt about simple chemical cells but I have no idea how to determine which cells will work and which will not and the working principle of those cells. I know that a chemical cell with $...
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2answers
1k 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
63 views

Calculating the standard reduction potential for the oxidation of water

I was working with Latimer and Frost diagrams for oxygen when I came across what seems to me a contradiction. From the Latimer diagram for oxygen below, we know the standard reduction potential for ...
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1answer
83 views

Half-Reactions of Hydroxide [closed]

The following is the equation I have: $$\ce{Ca(s) + 2H2O(l) -> Ca(OH)2 v + H2 ^}$$ I am tasked to write the half-reaction equations for both the oxidation and/or reduction process. So, currently ...
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5answers
438k views

Positive or Negative Anode/Cathode in Electrolytic/Galvanic Cell

In a galvanic (voltaic) cell, the anode is considered negative and the cathode is considered positive. This seems reasonable as the anode is the source of electrons and cathode is where the electrons ...
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2answers
360 views

Why won't removing the salt bridge cause the battery to recharge?

If I understand correctly, the salt bridge in a battery is used to move positive ions towards the side that is becoming more negative, and negative ions towards the side that's becoming positively ...