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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1answer
880 views

How to state something as strong or weak oxidising agents?

It is said that conc. $\ce{H2SO4}$ is a strong oxidising agent. Why is it regarded as strong? In case of acids, we say something that fully ionizes in an aqueous solution is a strong acid. But what ...
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1answer
985 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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1answer
56 views

Energy level of the product in a cell reaction

I'm very new to chemistry, so please try to be as plain as possible with your answers. I'm studying the chemistry of alkaline cells: The cell I'm interested in has the following chemical reactions ...
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1answer
842 views

Why is the maximum work done by a voltaic cell negative [closed]

The maximum work done by a voltaic cell is given by -nFE. Why the negative sign? From what I know, a battery does positive work on the load attached to it
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1answer
425 views

Disproportionation Reaction [closed]

This is the problem I am trying to balance for redox: $$\ce{HXeO4 -> XeO6^{4-} + Xe + O2}$$ It is supposed to be in a basic solution. However, my answer does not contain $\ce{OH-}$ on either side:...
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1answer
61 views

Corrosion rate of a metal in a liquid in relation to the size of electric current

I am trying to determine the formula for calculating the corrosion rate of a metal in a liquid in relation to the size of electric current that is passed between 2 metal plates. For example: we have 2 ...
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1answer
559 views

What is the difference between these two Electrochemical cell

can someone please tell me the difference between the 1st and 4th electrochemical cell in the picture, I understand that in the 4th cell Cu is 0.1M so does that make it nonspontaneous and would the ...
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1answer
538 views

How do you calculate the power (in watts) required per mole of product for or an electrochemical reduction?

Is it the transfer current density of the product multiplied by the overpotential?
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1answer
1k views

Is Q in the Nernst equation [Reduction]/[Oxidation] or [Oxidation]/[Reduction]?

The Nernst equation is given by : $$E_{\text{cell}} = E_0 – \frac{RT}{nF}\ln{Q}$$ I have seen ${Q}$ given as both ${[\text{oxidation}]/[\text{reduction}]}$ and ${[\text{reduction}]/[\text{oxidation}...
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1answer
991 views

How to use the Nernst Equation

So I understand the Nernst Equation, but I don't have some info. (Please bear with me, I'm in secondary.) I'm doing a Cu - Al cell. My E cell is negative (-1.33). Does this have an affect on the ...
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1answer
100 views

Electrolysis of molten sodium chloride [closed]

Can somebody explain me the electrolysis of molten $\ce{NaCl}$ via electrode potential? Reduction potential of $\ce{Cl-}$ is -1.36 V, while sodium metal is -2.76 V, but still sodium is reduced and ...
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1answer
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
4k views

Does the concentration affect the voltage in electrochemistry?

For my electrochemistry lab I'm using $\pu{10 mL}$ of $\ce{ZnSO4}$ and $\pu{10 mL}$ of $\ce{CuSO4}$ solutions connected with a salt bridge. I connect $\ce{Zn}$ metal and $\ce{Cu}$ metal to a voltmeter ...
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1answer
65 views

Redox - concentration cell

I'm studying galvanic cells and I've found a demonstration that lead me to an impossible result, so there must be a mistake, but I can't find what it is. My problem is about concentration cells made ...
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1answer
279 views

Relation of conductivity with electrode distance [closed]

Conductivity is defined as the conduction of ions when the distance between the electrodes is 1 cm and length is 1 cm. Say for instance we have a solution where the distance between the electrodes is ...
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1answer
4k views

Difference between Oxidation Potential and Ionization Potential [closed]

Ionization potential indicates a substance's tendency to loose electron and become a positive ion. So, a substance becomes ion more easily if it has a lower ionization potential (lower energy needed ...
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2answers
1k views

Why does the electrolytic solution need be electrically neutral in order for galvanic cells to work?

According to my book (and various other sources), the salt bridge in a galvanic cell serves to keep the solution electrically neutral. Yet I was not able to find any information on why the solution ...
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2answers
229 views

Oxidation States?

Metals in low Oxidation states are usually reducing agents. Is there any example of a metal in zero Oxidation state acting as an oxidizing agent.
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2answers
944 views

Concentration of hydrochloric acid for electrolysis?

How much hydrochloric acid (maximum) should I use to do electrolysis of water, and how much amount of voltage should I use to get the maximum of hydrogen and oxygen?
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0answers
10 views

Equation for Electrolyte concentration

What is the equation between conductance and concentration of electrolytes in a liquid? I know how to get the conductivity and thus electrolyte level. But was wondering if there is an equation to find ...
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1answer
45 views

Generating colloids / nano-particles from palladium and platinum wire

I know I can generate colloidal silver from the following link generate colloidal silver I now have 2 palladium and 2 platinum wires and would like to make one colloidal solution of palladium and one ...
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1answer
48 views

Why electrons move to Cu in galvanic cells?

I'm student who learning about chemistry, and I got problem about understanding why electorns move to Cu in galvanic cells. Let's think the reason for electrons going to Cu is that the standard ...
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1answer
53 views

What do electrons usually do when lead acid battery is idle?

Lead acid batteries operation are governed by Redox reactions for charging and discharging. But, what do electrons usually do when lead acid battery is idle? And why? Assumptions: Say more ...
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1answer
124 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
136 views

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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1answer
47 views

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
44 views

What drives the redox reactions in a standard hydrogen electrode?

In this video, the SHE half cell has two redox reactions occurring i.e. $$\ce{2H+ (g) + 2e- <=> H2 (g)}\\ \ce{H2 (g) <=> 2H+ (g) + 2e-}$$ But how can a single half cell initiate the two ...
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1answer
59 views

Number of electron for complete Discharge [closed]

What is the answer for question 17 and what is mean by "number of electrons for complete discharge?" Which of the following needs the largest number of electrons for complete discharge during an ...
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1answer
475 views

How&why does change in concentration affect cell potential

I'm a bit confused about why (in 1c) if the air pressure is lower, and there is a lower concentration of oxygen, why the cell potential decreases. It checks out fine with the Nernst Equation, but ...
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1answer
26 views

Which species are oxidized and reduced when sufficient voltage is applied?

For example, you have two salts in a solution. Say one of the species half reaction requires 1V (standard electrode potential), and another requires 3V, and you have a current running through the ...
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1answer
67 views

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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1answer
48 views

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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1answer
321 views

Galvanic/Voltaic Cell: Does Cell Voltage Change When A Resistor Is Connected?

I tried making a lead acid battery. After charging for about 10 minutes, I connect the voltmeter in parallel to the cell and see that there is around a 1.2V (which is quite lower than what I predicted)...
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2answers
390 views

How connecting galvanic batteries in series actually works. “In Series” detection experiment

How I am interested in understanding what is the actual mechanism behind increasing potential in simple galvanic cell connected in series. Almost all explanations I found on internet are more like ...
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1answer
1k views

Why is the standard reduction potential of an anode negative in a galvanic cell?

It makes not intuitive sense to me why something can have a negative voltage , I understand the concept of voltage drop , but voltage is not being dropped in the anode so why would it be negative ?
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1answer
1k views

How does electrolytic conduction depends on the size of ions & their solvation?

The textbook says, The smaller the effective size of the ion after solvation, the greater will be its conducting power." But, on the Internet, it is explained as follows: Radius decreases, ...
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1answer
455 views

electrochemical (Galvanic) cell solution purpose [closed]

I will try to rephrase my confusion: I am not sure if the redox reactions occur in Galvanic cell because of the wire connecting the 2 metals or because of the solution causing electrons to leave the ...
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1answer
335 views

In a galvanic cell from where does the electron in the external circuit come from?

I know that in a galvanic cell anode donates electrons through the external circuit. Is that the same electrons that the electrolyte gives it ?
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1answer
211 views

Why do we talk about hydrogen evolution for the corrosion of aluminum?

During the corrosion of aluminum, we have the oxidation of aluminum to its ionic form and this reaction is balanced by a reduction of ions in solution. So basically it is the reduction of $\ce{H+}$ ...
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2answers
435 views

How do galvanic cells work?

I was wondering how a galvanic cell works If you look at the picture below, if I have magnesium metal in sulfuric acid, will the metal react with the acid to be then turned into magnesium ions and in ...
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1answer
608 views

Immersing copper and zinc in hydrochloric acid

I am wondering what would happen if a metal strip of copper and a metal strip of zinc were immersed in solution of $\ce{HCl}$ in standard electrochemical conditions. I have calculated the standard ...
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1answer
579 views

Electrolysis and reduction potentials [closed]

Why does the hydrogen gets reduced at the cathode and not $\ce{Na}$ when aqueous solution of brine is subjected to electrolysis? My book says because discharge potential of hydrogen is lower than ...
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1answer
154 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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1answer
364 views

Flow of current in graphite [duplicate]

Why current flows through graphite if we join the poles of a battery to it horizontally and why not vertically?
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1answer
413 views

what is meant by stability and potential energy of molecules in cases of formation of bonds?

molecules form chemical bonds in order to gain stability. it is said that forming bonds leads to lower potential energy of molecules and makes them stable. what does stability mean? how formation of ...
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3answers
1k views

how to separate aluminum from aluminum alloy

In an attempt to produce aluminum oxide ($\ce{Al2O3}$) also known by alumina I try it out to dissolve two old hard drive frame in brine solution one as the cathode and the second as anode, in the ...
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4answers
114 views

Reduction Potentials [closed]

Standard electrode potential values can be used to judge the reducing ability of a metal. When I was introduced to this topic a simple picture was painted: you put a metal into a solution of its ions. ...
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1answer
358 views

Water colour changes to yellow after electrolysis [closed]

A salesman recently conducted electrolysis experiment on 4 samples of water-- river water,tap water, his own water and water from Aquaguard RO filter. The colour change after electrolysis on different ...
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1answer
128 views

If two atoms “fight over” one electron, who will win? [closed]

If two atoms of different elements are both missing exactly one electron in their valence shell so that they have a charge of +1 and we place an electron between them, exactly in the middle. Which ...
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1answer
57 views

Does this image represent a molecule? [closed]

PLease help me to define this, Thank you, Bruce