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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1k 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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26 views

How is $\ce{CuSO_4}$ formed when a soultion of $\ce{H_2SO_4}$ is electrolysed? [closed]

The ions in solution are $\ce{OH^-}$,$\ce{H^+}$, $\ce{Cu^2+}$, $\ce{SO_4^2-}$. I also know that at the cathode $\ce{H^+}$ will be reduced, hence forming hydrogen gas. Where and how does $\ce{CuSO_4}$ ...
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0answers
38 views

Electrolytic Cell [closed]

I was wondering how the concentration of an electrolyte effects the metal production in an electrolyte? It would be great if could get a formula to represent impact of concentration on mass of metal ...
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1answer
89 views

What is the meaning of thermodynamic tendency?

While giving a test, I encountered a question which was as follows Lead reduces $\ce{NO_3^-}$ into $\ce{NO}$ and $\ce{NO_2}$ depending on the concentration of $\ce{HNO_3}$ in solution. Assuming that $...
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1answer
64 views

Electrolysis of water using different kind of electrode and electrolyte safest as possible for splitting demonstration

I am planning to electrolyze water for an experiment. However, I have limited resources and want to do it as safely as possible The resources that I have: $\pu{12 V}$ DC battery Graphite (in the ...
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1answer
24 views

Is there a generalize-able relationship between Ecell and T for a galvanic cell?

Is there a generalize-able relationship between Ecell and T for a galvanic cell (assuming constant concentrations of all components)? (ie: higher temp = bigger/smaller Voltage) Or is it entirely ...
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1answer
27 views

Do the cathodes of all batteries increase in mass as the battery is used?

I understand the mechanism behind the cathode's increasing mass in many batteries. As the cathode receives electrons, ions are reduced to form atoms. In short, more electrons equals more mass in the ...
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1answer
37 views

How long do rechargeable Batteries last vs Standard Batteries?

Ordinary Batteries will deplete most of their Power in a 10 year period. What happens to rechargeable Batteries? How long would they still functin properly? Hope this is the right community for this ...
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1answer
171 views

Role of potassium hydroxide in alkaline battery?

Is the role of potassium hydroxide ($\ce{KOH}$) in an alkaline battery to provide hydroxide for the reaction with zinc? Would the battery cease to work if $\ce{KOH}$ was removed and only $\ce{OH-}$ ...
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1answer
2k views

What is the relationship between concentration and voltage in a galvanic cell? How do you calculate the theoretical?

I am a year 12 Chemistry student and I was wondering if you could help me with some questions I have about a Galvanic cell experiment? I am doing an experimental report in Chemistry. The experiment I ...
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1answer
74 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
168 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
352 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
84 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
94 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
162 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
1k 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
39 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
75 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
52 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
411 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
638 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
2k 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
673 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
510 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
214 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
526 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
661 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
837 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
2k 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
279 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
580 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
686 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
320 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
240 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
78 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
234 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
58 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
180 views

Does this image represent a molecule? [closed]

PLease help me to define this, Thank you, Bruce
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1answer
399 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
64 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
14k 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
47 views

What causes the voltage potential in a chemistry battery

Consider a simple chemistry battery: Zn and Cu with H2SO4 as the electrolyte. The electron will travel from Zn to Cu. And at the Cu side, H ion will get electron and turns to H2. If the circuit is ...
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1answer
40 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
53 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
89 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
43 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
80 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
552 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 ...