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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2answers
517 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
659 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
815 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
1k views

Why does increasing the concentration of the salt bridge in a galvanic/voltaic cell increase voltage?

I recently set up an experiment with 1M half cells made up of zinc and copper nitrate. They were connected with a sodium nitrate salt bridge of varying concentrations. As the concentration doubled 5 ...
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1answer
269 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
561 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
668 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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2answers
261 views

What is the essence of chemistry? [closed]

I am an engineering student who loves physics but didn't quite enjoy chemistry. a. When I was in high school chemistry to me was something not as inspiring as physics but in which I couldn't solve ...
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4answers
225 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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2answers
51 views

If the current is kept to zero in a potentiometric cell then how do electrons move from one electrode to the other? [closed]

If the current is kept to zero then how do electrons move from one electrode to the other electrode? How would the reduction happen if electrons don't move from one electrode to the other electrode?
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1answer
220 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
455 views

Why is cell potential an intensive property? [closed]

I've heard that cell potential is an intensive property. However, we know that an intensive property does not depend on number of moles, mass, or concentration of the substance involved. However, when ...
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1answer
53 views

Where do the electrons in lead–acid battery come from? [closed]

$$ \begin{align} \ce{PbO2 + H2SO4 &-> PbSO4 + H2O + O} &\quad &\text{(anode)}\\ \ce{Pb + H2SO4 &-> PbSO4 + H2} &\quad &\text{(cathode)} \end{align} $$ The cathode’s $\ce{...
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1answer
141 views

Does this image represent a molecule? [closed]

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

why molecules gain energy when heated?

molecules in solid or liquid or gas gain kinetic energy when heated. why is it like this? I request explanation in details please
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1answer
52 views

Could such a galvanic cell exist

Imagine I have a galvanic cell where in one half cell there is a lump of potassium metal and molten KOH electrolyte, and in the other an inert electrode, as well as a molten KOH and the less active ...
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2answers
63 views

Finding the pH of the solution

In this video, at 3:30 min professor solves two equations $$\ce{H2O —> H+ + OH-}$$ and $$ \ce{HCl —> H+ + Cl-}$$ and deduces $[\ce{H+}] = [\ce{Cl-}] +[\ce{OH-}]$. How come this happen from ...
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1answer
13k views

Direction of flow of current in electrolytic cell [duplicate]

In an electrolytic cell, does current flow from Anode to Cathode or Cathode to ...
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1answer
26 views

What determines the product at the anode/cathode of a electrolytic cell with an aqueous solution?

If you perform electrolysis on Aqueous Sodium Chloride of various concentrations, how does the product at the anode change but the product at the cathode does not? What is the mechanism behind this ...
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1answer
37 views

Corrosion rate of aluminium

In which conditions the corrosion rate of aluminium is faster? a) acidic conditions b) neutral c) alkaline conditions I know that corrosion can be in a and c cases but I dont know when it'll be faster....
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2answers
76 views

What starts the reaction in a voltaic cell?

In a zinc-copper voltaic cell, What causes the initial electron movement from the zinc to the copper? I understand that copper would pull the electrons more strongly than zinc, but only if it is ...
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2answers
42 views

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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1answer
74 views

Why the electrolyte is made up of the same metal which is being electro refined? [closed]

For example for the electrorefining of Cu the electrolyte is CuSO4... WHY the salt of the same metal is used as an ELECTROLYTE..??
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1answer
479 views

Why does molar conductivity depend on the volume of the solution? [closed]

I have been searching the answer to this question everywhere and (almost) the only answer I get is to formula based: ‘Since molar conductivity = k / M = k/1/V for one mole = kV Therefore molar ...
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1answer
27 views

If all the points on my graph fit on a logarithmic and polynomial trend line, how do i justify which trend line i should use? [closed]

My graph is mass of deposit vs concentration. The mass of deposit increases with concentration.
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1answer
64 views

how can I measure the pH of a HF:H2O:CH3OH solution? [closed]

how can I measure the pH of a HF:H2O:CH3OH solution? more specifically, how can I precisely and accurately measure the H+ ion concentration?
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2answers
1k views

What happens when two galvanic cells are placed in series

I understand how a single galvanic cell works, and the relation of equilibrium and the Nernst equation. But this appears to contradict the higher voltage in a series configuration because it ...
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1answer
67 views

Salt bridge confusion :(

How exactly does a salt bridge close the circuit? I understand its role of neutralizing the solustions but I can't see how it forms a complete circuit. Do charges flow back to the anode through it? ...
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1answer
55 views

Why is it bad to charge a phone to 100%? [duplicate]

I see everywhere that a phone should ideally be between 20 and 80% to work efficiently, but I don't understand why, in an electrochemistry point of view. (I'm not talking about the fact that ...
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1answer
52 views

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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1answer
339 views

Electrochemical cells. Why is a salt bridge needed at all when the system is open? [closed]

I get that the purpose of salt bridges is maintaining the amount of negative and positive charges in the solutions of two connected half-cells when electrons flow from one to the other. But when the ...
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1answer
27 views

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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2answers
319 views

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
3k views

How do acids conduct electricity with H+ ions?

I know that ions can conduct electricity, but H+ ions has no electrons! How can it conduct electricity then. Like if we were talking about Cl- or Na+ then these ions do have electrons. But how can ...
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0answers
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Entropic factor of electron-positron annihilation

In this question, user Nicolau Saker Neto states that "The distinction between enthalpy and Gibbs free energy in such subatomic reactions is completely negligible, as the entropic factor is ...
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1answer
215 views

What is the emf of a galvanic cell?

I am getting confused between EMF and potential difference of a cell. But i know that when a charge moves against an electric field it's potential energy increases which can be used to do some work. ...
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1answer
305 views

Rusting of iron is quicker in saline water than in ordinary water [duplicate]

I feel so because, saline water has more more electrons and because of that there will be oxidation will take place faster and hence the overall process will speed up. Is this explanation good enough ...
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1answer
226 views

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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2answers
58 views

Would a hydrogen/oxygen fuel cell be a good choice for energy storage and generation in H2 rich atmospheric environments?

So imagine an atmospheric probe sent to enter the atmosphere of a giant gas planet. There would be no need to store hydrogen since a compressor or an inlet with sufficient dynamic pressure would allow ...
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1answer
79 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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1answer
2k views

How do I determine which is the reduction reaction in a hydrogen peroxide and potassium permanganate solution?

How was it determined that $\ce{MnO4-}$ was reduction, and $\ce{H2O2}$ was oxidation? Also, why wasn’t the equation $$\ce{MnO4- + 2H2O + 3e- -> MnO2 +4OH-}$$ used? Or the $$\ce{H2O2 + 2H+ +2e- -&...
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1answer
46 views

Can a galvanic electrochemical cell produce current only one time without a salt bridge?

I think that galvanic cell produce current only one time without salt bridge. Potentional difference of both the electrodes are different and the electrons flow till their difference becomes same.Salt ...
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1answer
332 views

Protonation of nitric acid [closed]

I found that reaction: HNO3 + 4.1633363423443E-17 H3O = NO2{+} + OH{-} Please help me understand " 4.1633363423443E-17" term.
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1answer
552 views

Can we create a galvanic cell with only half a cell connected to the ground? [closed]

I have a question about electrical potential in galvanic cells ,suppose that we have only half a cell wich means that we have only one Ox/Red couple (one metal and the other as ionic solution ...)...
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2answers
92 views

Confusion regarding the positively charged copper electrode in a Daniell cell [closed]

Suppose I bought a newly manufactured Daniell cell then in this situation, can someone explain what all will be going on at the zinc and copper electrode? (Since it is newly manufactured and not used ...
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1answer
44 views

Balancing simple Redox equation [closed]

How would you balance these two redox equations? Would you add a '2' in front of Pt2+ and a '2' in front of H+ ?
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1answer
256 views

Is it easier to oxidise iron(II) to iron(III) in acidic or alkaline solution? [closed]

Is it easier to oxidise $\ce{Fe^2+}$ to $\ce{Fe^3+}$ in acidic or alkaline solution? $$ \begin{align} \ce{Fe &-> Fe^2+(aq) -> Fe^3+(aq)}\\ \ce{Fe &-> Fe(OH)2 -> Fe(OH)3} \end{align}...
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1answer
191 views

Why is it necessary to bubble hydrogen through the electrolyte in a hydrogen electrode? [closed]

I searched from the internet but i got confused. I was not sure about my answer.
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1answer
57 views

galvanic cell vs electrolysis [closed]

At school(high school), to calculate the voltage needed for electrolysis, we calculate the voltage produce if the elements were in a galvanic cell, preceded by a minus. So if a galvanic cell with Cu ...
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2answers
1k views

water in redox reactions [closed]

why water can't react as anode , with metals , in a redox reaction? while studying electrochemistry, i passed through a table with certain metals , all having voltage (potential energy) less than ...