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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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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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Can electrolysis be performed on gases?

For example, a Van de Graaff generator could produce voltages sufficient to polarize the gas, the molecules of which would then separate according to the relative difference in their ionization ...
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How to calculate ΔrHm? [on hold]

The question in regard is written as follows: Using the following reactions, calculate ΔrHm. a)Fe2O3 + 6HCl = 2FeCl3 + 3h2O b)Fe + 2HCl = FeCl2 + H2
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Electrolysis of Potassium Iodide [on hold]

Explain the change in pH durig the elecrolysis of KI using phenopthalie? I did the experiment in a U tube and the solution became pink colour in one side and the other side turned brownish red. That ...
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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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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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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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Some questions about electrochemistry [on hold]

1) Which of the following electrodes is used as pickup electrode for measuring redox potential of the system Cr3+/Cr2+? a) glass. b) zinc. c) copper. d) platinum e) silver chloride 2)...
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Cheaper ionic membranes

I am trying to make sodium hydroxide by electrolyzing table salt. I learned that I need cation exchange membrane (CEM) to prevent Cl- from crossing over to the cathode. The only example of CEM that I ...
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How do you use the Nernst equation on lithium ion batteries [on hold]

Anode: LiC6<=> C6 + Li+ + 1e- Cathode: Li+ + 1e- + CoO2 <=> LiCoO2 Overall: LiC6+CoO2<=>C6+LiCoO2 How do you apply the Nernst equation to this reaction? The concentration of solids is ...
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How Can I Induce Corrosion Electrochemically?

I'm very interested in measuring corrosion in metal alloys, particularly in salt solutions. I understand metals corrode over time, however, I was wondering if it's possible to electrochemically "speed ...
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what is the difference between oxidation state, charge and valency? [duplicate]

Is there any specific atom or compound or molecule possessing oxidation state different from charge and valency, so that we can clearly understand the difference between the three.
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Pale blue species forming during electrolysis of NaHCO3

I have a solution of 3500 ml $\ce{H2O}$ + 454 g $\ce{NaHCO3}$ in electrolysis at a potential of 12.5V using a lead anode and copper cathode. The surface areas aren't measured but they are enormous. I ...
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What material is my pot and what is coating it please?

I have a large beaten metal pot I inherited from my parents. It was kept outside and entirely tarnished black, except for places in the inside which had a gold appearance (it's obviously not a gold ...
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Equilibrium constant kp or kc? [closed]

In electrochemistry , nerst equation we use logkc if chemical species are in solution form but if gases then we use logkp. But kp and kc are different emf of cell will come out to be different by ...
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Is this the right way to make a diy battery? [closed]

I know that batteries run off redox reactions. Therefore can I choose an arbitrary reduction reaction in one half cell, an arbitrary oxidation reaction that will happen at room temperature for the ...
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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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Will there be electrical conductivity when two platinum metal strips are connecting with hydrochloric acid? [closed]

In the following set-up, the bulb does not light up. Which of the following changes may light up the bulb? (1) Replacing platinum electrodes with silver electrodes (2) Replacing silver chloride powder ...
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Electrolytic cell to remove soft solder from silver?

Hi my chemistry is pretty dire but have vague idea that an electrochemical cell could be used to remove soft solder (lead/tin probably) from a piece of sterling silver in need of a repair. The ...
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Why do power requirement figures for water electrolysis on the web seem to be wrong?

I need to calculate the power needed to electrolyse 1 mole of water for a project. We will either use Polymer Electrolyte Membrane Electrolysis or Alkaline Water Electrolysis, they operate on 1.75V-2....
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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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Entropy of lead storage cell

I am having trouble with calculating the entropy of a lead storage cell. The standard cell potential is given as $\pu{2 V}$ and the standard enthalpy change is $\pu{-306 kJ}$. I found out the Gibbs ...
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1answer
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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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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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Can ZnO act as a reducing agent for noble metals like Pd?

Palladium ions (e.g., $\ce{Pd^2+}$) can be reduced to $\ce{Pd}$ by more reactive metals such as zinc. Metal oxides such as $\ce{ZnO}$ are very stable but can its atoms in the oxide structure still be ...
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Do We change sign of electrode potential when reversing an equation?

I have a cell equation as: $$\ce{2Cr^0 + 3Cd^2+ -> 2Cr^3+ + 3Cd^0}$$ I am provided the standard reduction potentials as: $$\begin{align}\ce{Cd^2+ + 2e- &-> Cd} && E= \pu{-0.4V}\...
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Half-reaction for ammonium nitrate comproportionation into dinitrogen monoxide.

Ammonium nitrate comproportionates into dinitrogen monoxide in the following reaction: $\ce{NH4+ (aq) + NO3- (aq) -> N2O(g) + 2H2O (l)}$ I attempted to write the half-reactions by calculating ...
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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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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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Does electrolysis of aqueous tin (II) chloride produce Cl2 or SnCl4? Or both?

When applying a current to an aqueous solution of tin (II) chloride, tin crystals grow from the cathode. However, I'm not sure about the anode. It seems like there are two possible reactions: $$\ce{...
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Equivalent conductivity of barium chloride at infinite dilution

Find out the equivalent conductivity of barium chloride at infinite dilution given that the ionic conductivities of $\ce{Ba^{2+}, Cl-}$ are $\pu{127 ohm^-1 cm^2 equivalent^-1}, \pu{76 ohm^-1 cm^2 ...
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How to Separate Copper Nanowires in an Alumina Membrane

So, in my Chemistry Lab we had an experiment to use Whatman alumina membranes and GaIn eutectic to create Nickel nanowires through electrodeposition. So essentially Nickel wire electrode and alumina ...
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Why electrons are attracted by cathode in Voltaic/Galvanic cell

I studied that in the above setup electrons are attracted by Cu because of their reduction potential but they don't involve in reaction because of the d-bands of the electronic structure so Hydrogen ...
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Does the Nernst equation suggest voltaic cell voltage remains constant over time?

Say the following reactions are occurring in my voltaic cell: $$\ce{Mg->Mg^{2+} + 2e- +2.36V}$$ $$\ce{Cu^{2+} +2e-->Cu -0.34V}$$ Then, the Nernst equation would become: $$E_{cell}=2....
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Why is the current draw dropping in water electrolysis

We've done an experiment regarding water electrolysis. Basically, we just separated the oxygen and hydrogen gas in a beaker that contains a magnesium sulfate solution. We set the power supply voltage ...
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Using a significantly large metallic sphere, could we draw out the electrons from the negative terminal of a battery?

I've pored over many articles on electrochemical cells, and I understand that on the oxidation side of a zinc-copper Daniell cell, the anode is highly negatively charged because zinc participates in ...
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Troubleshooting electrochemical batteries

For my science classes, I have built multiple types of electrochemical batteries utilizing oxidation-reduction reactions, and I have demonstrated that they each produce potential difference across the ...
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1answer
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How does an electrolyte conduct electricity at low potential?

My understanding is that electrolytes conduct electricity by: 1) movement of ions, the negative ions migrate to the positive electrode and vice versa. This is however not enough, if these ions just ...
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Is it possible to generate electricity by using two inert electrodes in a galvanic cell?

The Daniell cell has two active electrodes, meaning that both the copper and the zink electrodes participate in the redox reaction. However, in a lemon battery for example, the copper electrode is ...
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What is the electrode potential at the equivalence point if concentrations of titrant and titrand are going to be zero?

Let's assume that the titrand is $\ce{Fe^2+}$ and the titrant is $\ce{Cr2O7^2-}$. Then $$E = E^\circ_\ce{Fe^{2+}/Fe^{3+}} - \frac{RT}{nF}\ln\frac{\ce{[Fe^{2+}]}}{\ce{[Fe^{3+}]}}$$ $$E = E^\circ_\ce{...
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1answer
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Does anything get precipitated in the half cells during the action of a salt bridge? [duplicate]

In the Zn/cu cell, once the reaction starts, excess ions begin to accumulate in both the half cells. To maintain the electrical neutrality, a salt bridge is used. how does the salt bridge actually ...
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1answer
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what should be the onset potential using cyclic voltammetry?

I am working for PEM fuel cell cathode material. I am confused regarding the onset potential determination for my catalyst (CV attached, fig 1 is complete CV while fig 2 is its zoom image for clear ...
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1answer
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Bonding metal pieces using electroplating - what's the process called?

So I think the title all most says it all - given say two pieces of copper can we make solid 'weld' using electroplating chemistry? If so whats the accepted terminology for this process so I can do ...
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Can a car's battery be used as a sacrificial anode?

The title of the question says it all. Can I hook the anode of my car's battery up to the car's shell and prevent it from rusting? Also would the car's battery get electrically charged from this?
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Why can't sulphate ion be discharged in the anode of electrolysis?

Given that there is an aqueous solution of sulfuric acid ($\ce{H2SO4}$), $\ce{2H+}$ is reduced in the cathode and $\ce{OH-}$ is reduced in the anode. Why is $\ce{OH-}$ preferentially discharged over $\...
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Confusion about the relation between gibbs free energy and electromotive force

$$\Delta G = -nFE$$ My textbook says that we can measure that this $\Delta G$ is measured when the work is done reversibly. But my confusion is how will we work reversibly when we have an ...
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Does concentration remain constant in an electrochemical cell's half cells?

We have from Nernst equation: $\mathrm{E_{cell} = E^\circ - \dfrac{RT}{nF} \ln Q_c}$ But I was wondering that in a simple cell like Daniel cell if concentration of $\ce{Zn^{2+}}$ keeps increasing ...
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1answer
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Faraday's Law of Electrolysis problem

Question: How many moles of iron will by passage of $\pu{4 A}$ of current through $\pu{1 L}$ of $\pu{0.1 M}$ $\ce{Fe^{3+}}$ solution for $1$ hour. Assume $\ce{Fe^{2+}}$ is not present in the ...