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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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How does the cathode of an electrolytic cell drive the anode reaction?

Consider this electrolytic cell: In this cell, electrons from the anode of the battery travel to the cathode of the electrolytic cell, where hydrogen ions are reduced into hydrogen gas. This drives ...
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83 views

Extraction of metals using electrolysis

I came across a question that goes as: The electrolytic method of reduction is employed for the preparation of metals that are: Less electropositive Moderately electropositive Highly ...
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141 views

Anodisation of aluminium in sulfuric acid - Electrolysis reactions [closed]

As an experiment for electrolysis and to show how a metal can be protected of corrosion, I am trying to anodize an aluminium plate, using sulfuric acid as electrolyte. I know the aluminium plate is ...
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349 views

Effect of resistance (distance) on the voltage of a galvanic cell [closed]

I'm doing an experiment at school on the rate of reaction in galvanic cell so I wanted to question how the length of wires and the addition of different resistors could affect the rate of reaction. I'...
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Coins in an Electrolytic Cell [closed]

In attempting to reveal the copper under a quarter, I used alligator clips to attach the quarter and a clump of copper wire to opposite sides of the battery. I put the electrodes in a solution of tap ...
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1answer
114 views

Electrolysis puzzle

I created an electrolysis setup to study how different electrolytes, their concentrations, and the electric current affect the "speed" of the electrolysis process. With that in mind, I built a simple ...
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1answer
51 views

Does this image represent a molecule? [closed]

PLease help me to define this, Thank you, Bruce
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1answer
40 views

Will the electrolyte surface become charged if one electrode is raised out of solution?

What would the potential distribution be if I were to immerse a single inert (graphite) electrode in an aqueous solution with good ionic conductivity and hold it at a high (ca. $\pu{24V}$) potential ...
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56 views

Voltage applied when charging a galvanic cell

A working galvanic cell is constructed using an iron electrode in an iron(II) nitrate solution and a silver electrode in a silver(I) nitrate solution. When the cell runs down, it can be charged up ...
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731 views

Why does Hydrogen Peroxide decompose? [duplicate]

I understand that Hydrogen Peroxide decomposes into oxygen and water over time. But why exactly does it do this? Could someone give me an explanation down to the molecular level as to why and how this ...
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79 views

Calculating cell-potentials

I have measured the cell potential between a number of metals e.g. Ni, Pb, Al, Cu and Zn by constructing a galvanic cell and then used a voltmeter to measure the potential. Now, if I want to ...
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48 views

Why do electrons not flow through the electrolyte? [duplicate]

Why do the electrons not flow through the electrolyte instead of the external circuit in a electrolytic cell connected to an external circuit? I mean, if an electrolyte is a conductor why would the ...
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28 views

How does a glass pH electrode measure potential difference? [duplicate]

I think I have a basic understanding of how an ion-selective electrode (in particular the pH electrode) works. I've read that section of Harris's Quantitative Chemical Analysis many times. The gap ...
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84 views

Can a gas make a good wide spectrum radiation shield? Revised [closed]

Can an electrical current be applied to Oxygen inside a dome create a EM shield as a artificial geomagnetic field? $O_3$ is broke down by radiation but $O_3$ can be recreated by applying electricity ...
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3k views

Mechanism of Kolbe's electrolysis

For preparation of alkanes by Kolbe's electrolysis, I came across two mechanisms to explain the reactions taking place at the cathode. **OR** 1) Now, if ...
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1answer
68 views

Are my intuitions about how batteries work right? [closed]

Being really fascinated by how electricity actually works, I started studying batteries. I initilally understimated the complexity of this apparently-simple objects, and thorugh studies and researches ...
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134 views

What is the definition of current efficiency?

What is the exact definition of current efficiency of an electrolytic cell? I've looked online and there is no suitable answer to it. I thought current efficiency would be the amount of electrons ...
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931 views

Why is AC current used rather than DC current for calculating the conductance of a solution(see body)? [closed]

I was reading the answer of the above question from a book. it said that while using DC current, electrolysis occurs. Hence it affects the conductance of the solution. But if any gaseous product is ...
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587 views

Salt Bridges/Porous Disks

I am slightly confused about the concept of a salt bridge/porous disk. I understand that these are necessary in a galvanic cell since there is a charge buildup and the salt bridge and porous disks ...
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How does pH change during the electrolysis of water? [closed]

How does the pH change during electrolysis of a water and magnesium sulphate solution? Also, will this pH change happen every time? Does the pH change differently when there is just water in the ...
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Pourbaix diagram and the order of the species

Here is a Pourbaix diagram of iron: The line between $\ce{Fe}$ and $\ce{Fe^2+}$ is there because the Potential $\ce{Fe/Fe^2+}$ is -0.44V. The same applies for $\ce{Fe^2+/Fe^3+}$ with 0.77V. But $\ce{...
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1answer
61 views

How does the redox of a battery happen? [closed]

I tried to understand how does a battery work. After doing some research, I knew chemical reactions inside are key. But when I came across the reactions inside a zinc carbon battery, almost all ...
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2answers
553 views

Why are H+ and OH- ions preferentially discharged in the electrolysis of NaCl(aq)?

There are 4 types of ions in an $\ce{NaCl(aq)}$ solution: $\ce{H+}$, $\ce{OH-}$, $\ce{Na+}$ and $\ce{Cl-}$. According to the E.C.S. table, $\ce{H+}$ and $\ce{OH-}$ should preferentially discharge at ...
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Electrolysis of concentrated sulphuric acid

In my textbook it is given that for electrolysis of dilute sulfuric acid at anode following reactions can occur: At moderate concentrations $\ce{2H2O -> O2 + H+ +4 e-}$ And for high ...
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Type of floor for a chemistry lab [closed]

I'm currently building a small chemistry lab and I'm wondering about which type of floor would be the best to use. Currently I'm mainly doing electrochemistry experiments with lithium and other metals....
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2answers
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How can we directly add half cell potentials to measure the EMF of a galvanic cell?

We know that $E^\circ_{\text{cell}}=E^\circ_{\text{reduction at cathode}}+E^\circ_{\text{oxidation at anode}}$. For example, in a cell $\ce{Zn(s) | Zn^2+(aq) || Cu^2+(aq) | Cu(s)}$, $$E^\circ_{\text{...
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Electrodes involving sparingly soluble salts (Electrodes of the second kind)

Consider the sparingly soluble salt, $\ce{AgI}$ ($K_\text{sp} = 8.52\times10^{-17}$) and a silver electrode (Standard Reduction Potential = $\pu{0.799V}$). $\pu{0.02L}$ of $\pu{0.001M}~\ce{KI}$ ...
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Is this hybrid seawater fuel cell just a sodium ion battery?

This article describes a rechargeable hybrid seawater fuel cell where the cathode is just open seawater interfaced by carbon paper. The anode is a tin-carbon nanocomposite and the electrolyte is a ...
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1answer
262 views

Electrochemistry molar conductivity

Molar conductivity increases with decrease in concentration. This is because the total volume, $V$, of solution containing one mole of electrolyte also increases. It has been found that decrease in $\...
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2answers
193 views

Matching the NMR to a compound

I was given a molecule that I had to identify the NMR of. The molecule is 2-methylpent-1-ene (shown below): The correct NMR spectra for this molecule is: My question is, why is this the right ...
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Are there any compounds with these properties? [closed]

I'm looking for a chemical compound that satisfies the following criteria: Solid at room temperature Decomposes into gases, primarily oxygen when supplied with an electrical current, preferrably ...
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61 views

Electrolysis under high pressure

Suppose we submerge a bell-shaped electrolysis chamber, flip it under water to have it filled with water, flip it again (so that the top is closed and the bottom is open), and lower it deep into weak ...
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1answer
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Electrochemical manufacturing of small metal components

Metal crystals easily can be grown via electrochemical pathways. Copper is a great example of this. I recently had an idea of growing those crystals in controlled ways (i.e.: surrounding the electrode ...
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117 views

Meaning of electrochemical cell notation without a salt bridge

An electrochemical cell is shown here. $$\ce{Ag(s)~|~AgCl(s)~|~KCl(1M)~|~Hg2Cl2(s)~|~Hg(l)~|~Pt}$$ I am used to seeing cell representations with a $||$ for a salt bridge between the two electrode ...
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Can bronze be electroplated with zinc?

I had to have a motorcycle part cast in bronze that was originally steel. I want to electroplate it with zinc. Will this work? Thanks
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How to calculate the electrochemical potential of a cell using known half-cell potentials?

What is $E^\circ$ for the half-reaction representing the oxidation of $\ce{HOCl}$ to $\ce{ClO3-}$ given the equations below? \begin{align} \ce{ClO3- +6 e− + 6 H+ &= Cl− +3 H2O},& E^\circ &...
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Resistance of Electrolytes [duplicate]

During electrochemical experiments, we consider the resistance of the electrolytes. What exactly is causing the electrolytes to offer resistance to flow of charges in them? Also, does the resistance ...
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Can the choice of which reference electrode to use in a basic solution significantly affect the results?

I am performing a combined chronoamperometry/chronopotentiometry experiment in a solution of 0.1 M NaOH and with Ag/AgCl reference electrodes. I was initially told by someone that typically Ag/AgCl ...
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59 views

Current in a Concentration Cell

I would like to know if there is a simple function that gives the current as a function of time in a concentration cell. The current is measured in the wire connecting the two terminals of the cell. ...
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Suitable anode materials for electrolysis of water [duplicate]

I'm planning to electrolyze water as a personal project, but I'm not sure what materials can be used for my anode. I've heard stainless steel can produce hexavalent chromium, and noble metals like ...
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How come ∆G ≤ 0 is used for spontaneity in electrochemistry, not ∆G ≤ W(other)?

The spontaneity condition for a system at constant temperature and pressure in which the only type of work accomplished is of the $pV$ type can be expressed as: $$\Delta G\le0\tag1$$ In case of ...
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What exactly is an “electron-sponge”?

What exactly an "electron-sponge" [behavior/action/property/system] nickname is, and what makes a material an "electron-sponge" (preferably, quantitatively)? From what I found, it's typically a ...
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1answer
668 views

Best Settings for Electrolysis of water

I want to electrolyze water as a personal project, but I have found conflicting power recommendations on google. Some sources recommended a higher voltage, claiming that higher amps will just destroy ...
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1answer
659 views

Cell notation for the lead-acid battery

Reactions for the lead acid battery are: $$ \begin{array}{} \text{Oxidation}&\ce {Pb(s) + HSO4^-(l) &-> PbSO4(s) + H+(l) + 2e-}\\ \text{Reduction}&\ce{PbO2 + HSO4^-(l) + 3H+(l) + 2e- &...
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Understanding an Electrochemical Cell

Up there is a Electrochemical cell. I have marked the anode (-) and cathode (+) (by taking help from google) but I still need the explanation because such assignment of charges on given electrodes is ...
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1answer
39 views

Determining the theoretical mass of gas produced through the process of electrolysis

I have a question that has been stumping me for quite some time. I wish to calculate the mass of gas that is produced from varying concentrations of salt (NaCl) through the process of electrolysis. I ...
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Missing ion concentration when applying Nernst equation to the given cell

Find the $E_\mathrm{cell}$ from the given cell diagram $$\ce{A | A^3+ (\pu{0.05 M} || B^3+ (\pu{0.01 M}) | B^2+}$$ $$E^\circ_\ce{A | A^3+} = \pu{1.66 V}$$ $$E^\circ_\ce{B^3+ | B^2+} = \pu{-0.77 ...
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Reaction characteristics of alkaline battery [closed]

I'm currently struggling with understanding why electrochemical reactions take place the way they do. For example, in an alkaline-manganese battery manganese-dioxide is getting reduced by reacting ...
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Relationship between Yield and Applied Potentials

This question revolves around this question from Atkins' Chemical Principles 5th ed., Chapter 13, Question 13.116: Consider the electroplating of a metal $+1$ cation from a solution of unknown ...
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1answer
86 views

Which is discharged? [closed]

Why Na+ ion is discharged at cathode rather than H+ ion when Mercury is used as cathode in electrolysis of aqueous NaCl solution ?