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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56 views

Can the electrochemical stability of a aqueous KOH solution be increased by adding more KOH?

My goal is to increase the efficiency of a nickel-iron battery. One of the options to reach this goal is:suppressing the hydrogen production. Due to electrolysis, the electrolyt will start ...
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870 views

Sodium Sulfate or Sodium Carbonate for electrolysis in water

I am not a chemist but I have a question regarding electrolytes in electrolysis. I have done a lot of reading but cannot find the answer I'm looking for regarding Sodium Sulfate (or Sulfide) I intend ...
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14 views

What does a sigmoidal and non-sigmoidal shape of a oxygen reduction reaction (ORR) voltammogram mean?

While testing materials for their ORR performance, one can encounter linear sweep voltammograms that have a well defined diffusion plateau and a good sigmoidal shape. On the other hand, the opposite ...
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70 views

Questions About an Appropriate Textbook on Electrochemistry for Self-Study

Apologies if this is a somewhat frequent request (I promise I did scour various sources before posting, but none quite applied to me), but I was hoping for some insight from the community regarding an ...
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1answer
108 views

Redox and anode/cathode in lead acid battery

I have watch a video about lead acid battery and I am very confused about the way the half reactions are labelled. I have learned that oxydation is the loss of electron (so it's the half reaction with ...
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97 views

How does a body lose electrons? [closed]

If there is a Na and cl in solid form , There will be atoms inside of them.How do they lose electrons ?.We know solid body has a structure and covering.Just like you can touch is the covering of table ...
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80 views

How to make krypton gas glow

So hypothetically, if one was to buy krypton and wanted to make it glow, would a little tesla coil be enough to make it glow? If not, what would be enough? And would one be able to make it glow ...
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51 views

What is the relationship between the stability constant of a copper (II) electrolyte complex ion and the output voltage Ecell? [closed]

As a part of a school investigation I constructed a voltaic cell experiment where for each run I added a different ligands to the copper (II) sulfate half-cell electrolyte in a daniell cell to see if ...
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81 views

Calculating the cell potential of a half cell from two half cell equations [duplicate]

I understand the premise of the question and how to solve it but I don't quite understand why I'm a factor of 2 out: Construct a potential diagram (at $\mathrm{pH} = 0$) for the reduction of aqueous $...
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60 views

Easiest/Fastest way to obtain a good quantity of fine Iron powder? [closed]

I am wanting to make a reasonable quantity (10-100g) of iron powder that I can use to visualise magnetic fields (by putting the powder in a thin layer between two transparent materials). The finer the ...
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36 views

In electrophoresis, are positive and negative molecules obviously separated?

I have just studied electrophoresis in biochemistry. The charged particles move to the oppsite charged electrodes whose speed is depended on their particle size. If that so, are negative and positive ...
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335 views

Copper anode dissolves in electrolysis of copper sulfate solution [closed]

I did an experiment with copper sulfate where you place two copper rods in an aqueous solution of copper sulfate. You apply an electric current and copper metal builds up on the cathode. I noticed ...
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1answer
102 views

Graphene in Lithium-ions batteries: why?

I have recently been reading about the amazing discovery of a super-material: Graphene. This one carbon-layer chemical is not only one of the most resistant materials ever known, but also one of the ...
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34 views

Methane Sensor electrochemical reaction

When using a methane sensor a voltage is applied and much like electrolysis if the voltage is above the decomposition potential a reaction happens. Flammable gasses like methane are easily oxidized ...
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87 views

Why is Sodium Transported Across the Cation Exchange Membrane in the Chlor Alkali Process?

In the Chlor Alkali Process, a sodium ion is transported across a cation exchange membrane to create NaOH in the Anode Chamber: The Half reactions are: 2Cl− → Cl2 + 2e− and 2H2O + 2e− → H2 + 2OH− and ...
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Is there a way to theoretically estimate the overpotential losses in a battery?

Me and my team are currently designing a battery and are looking to do some pre-experimental analysis of different battery chemistries based on their overpotential losses. I am aware of the Butler ...
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156 views

Cell potential for redox titration of iron(II) with cerium(IV) [closed]

Calculate $E_\mathrm{cell}$ for an electrochemical cell consisting of SCE and a platinum wire indicator electrode dipped in a titration vessel containing $\pu{25 ml}$ $(\pu{0.01 M})$ solution of $\ce{...
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96 views

How does current start to flow when galvanic cell is first connected?

Using the Daniell Cell as an example, where in the steady state we expect zinc to be oxidised and copper to be reduced spontaneously due to the overall reduction in Gibbs free energy, how does the ...
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57 views

Why do batteries drain so quickly if they are forced to draw more current than they normally do?

When a battery is pushed to use twice the current it normally does, it lasts for less than half as long before dying... In fact, batteries often come with a 'C' rating that gives you an idea of how ...
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55 views

How does work from other sources affect Gibbs free energy of the system?

In most physical chemistry textbooks, Gibbs free energy is given like this: $$\Delta_\mathrm rG = \Delta_\mathrm rG^\circ + RT\ln Q\tag{1}$$ and Gibbs free energy is part of this three-way ...
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645 views

Does changing the electrolyte concentration in the electrolysis of water affect the speed that hydrogen gas is produced at the cathode?

I am currently completing a Year 12 Extended Practical Investigation. Due to the lock-down restrictions we are unable to complete our own practical experiment and have been given sample answers with ...
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Can I use activated carbon electrod as a reference electrod in a pH meter instead of using murcury? [closed]

Activated carbon is less expensive than mercury . They are recyclable . Mercury is toxic. Nowadays activated carbon is being used in supercapacitors,Li-ion battery.
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136 views

Cell voltage with different n factors

I’m a bit confused regarding cell potentials. If I have two half reactions each involving a different number of electrons, there are two ways I can see to calculate the net emf of their cell: Simply ...
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176 views

Why does an electrochemical cell work?

My textbook says that an electrochemical cell works because of difference in reduction potential of two metals which cause one to lose electrons and other one to accept them. If a salt bridge is not ...
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111 views

Supporting electrolytes and increased conductivity?

Hi a question about supporting electrolytes (SE) I hope you can help with. I found some related questions here through searching but looking for a simple answer (if there is one!): If SE are ...
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56 views

How does a battery create a potential differece (voltage)? [closed]

I'm 15 and recently started electronics and I just had a question about batteries. (I've been told by people on physics stack exchange to come here to have my question answered). From what I ...
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341 views

Standard electrode potential of copper disproportionation

I am having some difficulty with the below. It says the standard potential for $\ce{2Cu+ (aq) -> Cu (s) + Cu^2+ (aq)}$ is $\pu{0.36 V}$. The relevant half equations are: $\ce{Cu+ + e- -> Cu}$ (...
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42 views

In Na extraction, is Ca2+ of CaCl2 reduced in addition to Na+ of NaCl in electrolysis

In Na extraction from $\ce{NaCl}$, $\ce{CaCl2}$ is added in electrolysis to lower the melting point of the mixture to about $\pu{750 ^\circ C}$. But doesn't $\ce{Ca^2+}$ cation compete with the $\ce{...
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What surface treatment can turn nickel black?

Questions: The detailed surface treatment to turn nickel plated steel black. The reaction mechanism of the process. Methods: (preferred) Anodizing, oxidizing : The only black nickel oxide is $\ce{...
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if I have concentrated acetic acid (99%) what are the out put gases during electrolysis?

If I use concentrated acetic acid (glacial acetic acid($\ce{CH3COOH}$)) as an electrolyte. What ions are produced at the anode and cathode? Can I get ethanol with it ($\ce{C2H6O}$)? If not, what would ...
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56 views

What is the effect of putting salt on water during electrolysis [closed]

I want to decompose $\ce{H}$ ion and $\ce{O}$ ion by putting carbon electrode in the water, but it look so slow. What if I put sodium chloride? Would putting $\ce{NaCl}$ have effect on output gas($\ce{...
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230 views

Would a voltaic cell still work if you replaced both the cathode and anode with a carbon/graphite electrode?

for example, in this cell: Zn(s)|Zn2+(aq)||Ag+(aq)|Ag(s) if you replace the silver cathode with a carbon electrode, i know it would still transfer electrons, but if you also replaced the Zinc ...
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43 views

Why I get acidic solution at brine anode?

I have decomposed $\ce{NaCl}$ solution (brine) with electrolysis and yield $\ce{NaOH}$ at cathode, at anode I got acidic while expected was $\ce{NaClO}$ (alkaline) if it is $\ce{HOCl + HCl}$. Where ...
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1answer
410 views

Electrolysis with baking soda solution, a penny as the cathode and graphite for the anode

I set up an electrolysis experiment to show my kids and wanted to explain to them what is happening. My setup has a penny as the anode and graphite for the cathode. The solution is water with baking ...
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135 views

White snow-like powder below sodium hydroxide solution [closed]

I have created sodium hydroxide solution with half cell brine electrolysis but, finally I got white snow-like insoluble powder sank below sodium hydroxide. What should I do keep or remove it?
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Conductivity of molten or aqueous salts [closed]

If there is a 1M aqueous solution of 1 liter NaCl (aq), and the molar conductivities of the solution and the chloride ions were found to be $x$ and $y$ respectively, is it accurate to say that the ...
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29 views

What is the relationship between current flow and low AC voltages within electrolyte solutions

I have recently been trying to find references or textbooks which may explain the principles of electrical current conductance within an electrolyte solution when low AC voltages are induced. Does ...
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664 views

What happens when you put a battery in saltwater? [closed]

If somebody puts a battery in a salt solution, what path do the electrons take?
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159 views

How to find number of moles of HNO3 behaving like acid in a redox reaction?

In the reaction $(1)$, how to find the number of moles of $\ce{HNO3}$, which is behaving like acid? The reaction is given as follows: $$\ce{Sn + HNO3 -> Sn(NO3)2 + NH4NO3 + H2O} \tag1$$ To find ...
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Conducting cyclic voltammetry in an air sensitive manner

Does anyone have suggestions on ways to conduct cyclic voltammetry on an air sensitive material without shipping the entire set up into a glovebox? This is for redox active organometallic compounds.
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122 views

How do you purify gases formed in electrolysis with a potassium hydroxide electrolyte?

I am interested in the $\ce{KOH}$ vapor that is released with my gasses during electrolysis. I have two questions. What would be the best place to start research on the $\ce{KOH}$ vapor produced in ...
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58 views

Overview of material characterization methods

I have been searching for quite some time now, but I feel like it is impossible to find some sort of chart where I can determine which characterization method (microscopy, spectroscopy, ...
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275 views

What is the physical explanation driving current flow in a concentration cell?

In a galvanic cell, current is driven because the species at the cathode is reduced by grabbing some electrons from the cathode. The cathode now lacks electrons so it pulls them from the anode. Now ...
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2k views

How is the formula of mean activity coefficient derived?

The mean activity coefficient is defiend as follows: $$\gamma_\pm = (\gamma_+\gamma_-)^{1/2}.\tag{1}$$ If Debye-Hückel equation $$-\log\gamma_i = 0.5z_i^2\mu^{1/2}\tag{2}$$ is used, then the mean ...
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35 views

Reason for no change in electrode potential in reference electrodes

Reference electrodes such as the saturated calomel electrode and silver chloride electrode have a constant potential because the $\ce{Cl-}$ concentration (or, to be more precise, the activity) is ...
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782 views

Why is the electrode potential for a cathode positive?

Electrode potential is the potential difference between the electrode and the surrounding electrolyte. If the potential of the cathode is positive this means that the potential of the electrode is ...
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52 views

Correlation between redox pseudocapacitance, surface area, and cell potential with metal oxide electrodes

I'm having difficulty intuitively reconciling two different ideas concerning metal oxide thin films in contact with aqueous solutions: 1) that charge storage by both redox pseudocapacitance and ...
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123 views

Cyclic voltammetry for irreversible reactions

I'm new to electrochemistry and I was wondering two things, sorry if these two problems are trivial but I just can't find anything close to this in the literature. First, the following reaction is ...
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288 views

Disproportionation of silver(I) in aqueous solution

Use the following equations to predict whether or not $\ce{Ag+}$ ions will disproportionate in solution: $$ \begin{align} \ce{Ag+(aq) + e- &-> Ag} &\qquad E^\circ = \pu{+0.80 V}\\ \ce{Ag^2+(...
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69 views

Proper method to electroplate aluminum?

I'm looking to plate some aluminum with silver using a basic solution. My first attempt was to use sodium carbonate to make silver acetate. I sped up the process using hydrogen peroxide. I used the ...

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