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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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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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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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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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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“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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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 ...
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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 the ...
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315 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,...
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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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640 views

Electrode potentials at interfaces?

My questions relates to the fundamental concept of electrochemistry, more specifically the electrode potentials. 1) First, why is there a potential difference at the interface of two phases? ...
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Reaction of an electrode

Why is the cathodic reaction of $I^-/AgI/Ag$ is $$\ce{AgI + e- -> Ag + I-}$$ but not, $$\ce{Ag+ + e- -> Ag }$$ whereas, in $Ag/AgCl(s)$, $KCl$(0.2M); it is $$\ce{Ag+ + e- -> Ag}$$
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How do the stored chemicals in batteries drive electronic current from their terminal to outside devices?

I have got around to at least read on Wikipedia, and it does not clarify how this works in any sensible manner. I wondered how the chemicals make electrons "move". How is the basic understanding of ...
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chemically inert molecule with piezoelectric properties

For a research project, I'm looking into existing chemical molecules that have the following properties: It is mostly chemically inert, safe for animals and children It exhibits piezoelectricity - ...
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In a battery what would happen if you had a perfectly uniform and pure cathode?

I have been watching some videos on how batteries work and they seem to talk about the cathode being the most important. I also watched another video a long time ago and while my memory is blurred it ...
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Why do batteries specifically vent *hydrogen* in the event of abuse?

When a battery is subject to overcharging or overdischarging (including attempts to recharge a primary cell), it may vent hydrogen. It seems that every type of electrochemical battery I've read about ...
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597 views

Electrochemical Cell

Now in an electrochemical cell , we make use of the fact that whenever there is a potential drop , electrons will flow from lower to higher potential as for a potential drop , there must be an ...
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Sulfuric Acid Resistance / Conductivity

I diluted sulfuric acid in deionized water in order to get a 10% $\ce{H2SO4}$ solution. I was going to use this solution as a cathode of a porous sample to measure its electrical properties. However,...
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What's the chemistry behind only charging a Lithium-ion battery to 80% capacity at most, to increase its lifespan?

What's the chemistry behind only charging a Lithium-ion battery to 80% capacity at most, to increase its lifespan? Over on the Skeptics StackExchange, a question has come up about charging Lithium-...
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How do I calculate partial pressure here?

I need some help with partial pressures of reactions for a fuel cell project. The overall reaction for a fuel cell is $$\ce{H_{2} +\frac{1}{2}O_{2}->H_{2}O}$$ Which means that the mole fraction ...
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Lewis model and modern physics

Electron affinity of chlorine = -349 kJ per mole. And, first ionization energy of sodium = 496 kJ per mole while energy required for combining= 147 kJ per mole. Isn't it a contradiction against ...
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Why do aqueous solutions always have to be electrically neutral?

I was reviewing some analytical chemistry and stumbled upon a section that explained the imperfection of using a salt bridge. It said that the using dissimilar ions is a problem because in, for ...
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313 views

Why does electrolysis take so much time?

What makes electrolysis or electroplating take so long ? What stage takes longer when ions are attracted to electrodes or when they gain or lose electrons at electrode. And if we are talking about an ...
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Is it possible to form bubbles of ionized hydrogen and ionized oxygen under the right pressure/temperature conditions during electrolysis of water?

When we run a current through water (pure or not), $\ce{O_2}$ forms at the anode while $\ce{H_2}$ forms at the cathode. If I understand correctly, as water is already slightly ionized, $\ce{H}$'s snap ...
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Measuring distance in a conductive liquid

What is needed to measure distance between two electrodes imersed in seawater ? I have tried measuring the voltage across the path (a suposed resistance) with a constant current source (about 10uA) ...
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Electronegativity

Why is the Electronegativity difference for atoms in bonding uncertain while determining what the compound will be? According to the IB(International Baccalaureate) they say that the ...
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What is a 'Trace Crossing'?

I'm reading about electrodeposition of conductive polymers in a chemistry textbook, and the author mentions 'trace-crossing' in the 'potentiodynamic response'. From the context I can figure out that '...
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Thought Experiment: Applying a high frequency high voltage to methane

I am in the process of constructing a kitchen waste digester (vegetable/fruits) from which, hopefully, over time adequate methane may be collected to burn. The digester won't be complete for several ...
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Can we separate positive ions from negative ions in a solution?

Can we make a solution containing only positive ions by using electrodialysis but instead of using 2 kinds of membrane (one blocks the positive ions and one blocks the negative ions) we can use only ...
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Would the detaching of dendrites from electrodes in a cell, result in the crystal dissolving back into the electrolyte?

Dendrites that form on the electrodes of cells shorten the cell's lifetime, and result in reduced capacity before the end of life. If the dendrites could be detached from the electrode, would they ...
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Galvanic corrosion between nickel brass nut and stainless bolt

I am planning to install something on a boat that will be in salt water, and my question is, will the nickel plated brass fastener not corrode if I connect it to stainless steel? I looked it up on ...
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What's the name of this electrolysis device?

I've seen it in a couple of videos, it's used to electrolyze water in 2 different containers at the same time to make a comparison and thus is very handy. What is it called (besides just a ...
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Will the current at the inversion potential of a CV trace asymptotically approach zero?

Reading up on the theory of cyclic voltammetry, I note that the current at the inversion potential (that is, the point at which the applied potential goes negative) in every reversible CV trace I have ...
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What determines the electronegativity of an element?

Is it possible to work out without post-Bohrian mathematics?
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Why does an ideal capacitor give rise to a rectangular cyclic voltammogram (CV)?

This question is sort of a sequel to my previous question about cyclic voltammetry (CV). One of the responses made reference to the fact that an ideal capacitor gives rise to a rectangular cyclic ...
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How does conductivity work for non-redoxed ions?

Related (very similar, but here I want a mechanism) https://physics.stackexchange.com/q/21827/7433 By the Kohlrausch law, all ions contribute to the conductivity of an electrolyte. Now, as I ...