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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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Degradation of anode in electrolysis

In my electrolysis experiment, I used a 9 volt battery, 1:100 mL baking soda:distilled water, and stainless steel electrodes. I noticed that the anode degraded faster than the cathode. Out of ...
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Can electrolysis be performed on gases?

For example, a Van de Graaff generator could produce voltages sufficient to polarize the gas, the molecules of which would then separate according to the relative difference in their ionization ...
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How to calculate ΔrHm? [on hold]

The question in regard is written as follows: Using the following reactions, calculate ΔrHm. a)Fe2O3 + 6HCl = 2FeCl3 + 3h2O b)Fe + 2HCl = FeCl2 + H2
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Electrolysis of Potassium Iodide [on hold]

Explain the change in pH durig the elecrolysis of KI using phenopthalie? I did the experiment in a U tube and the solution became pink colour in one side and the other side turned brownish red. That ...
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what is the exact meaning of oxidation state? [duplicate]

can you mention the concept of oxidation state without its simple definition i-e it is the apparent charge +ve or -ve.....😪 I found these in wikipedia but didn't understand."Conceptually, the ...
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why do I get chlorine gas production during electroetching?

I was electroetching stainless steel plates with table salt as electrolyte and the power supply was providing 5V, 6A when I placed the anode and cathode about .25 inches apart. I started smelling a ...
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Which etching process is better, photochemical or electrochemical?

My boss and I are experimenting with several different ways to micro machine .01" and .005" stainless steel. When I look up how it's done professionally, I see an overwhelming majority of companies ...
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42 views

Pale blue species forming during electrolysis of NaHCO3

I have a solution of 3500 ml $\ce{H2O}$ + 454 g $\ce{NaHCO3}$ in electrolysis at a potential of 12.5V using a lead anode and copper cathode. The surface areas aren't measured but they are enormous. I ...
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Changing the CO2 concentration (adding or subtracting) inside a sealed vessel?

I am looking for a method of modifying the CO2 concentration inside a sealed container that is both precise and repeatable (C02 needs adjustment every time the container is sealed, also need to be ...
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2answers
31 views

How Can I Induce Corrosion Electrochemically?

I'm very interested in measuring corrosion in metal alloys, particularly in salt solutions. I understand metals corrode over time, however, I was wondering if it's possible to electrochemically "speed ...
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17 views

Some questions about electrochemistry [on hold]

1) Which of the following electrodes is used as pickup electrode for measuring redox potential of the system Cr3+/Cr2+? a) glass. b) zinc. c) copper. d) platinum e) silver chloride 2)...
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Cheaper ionic membranes

I am trying to make sodium hydroxide by electrolyzing table salt. I learned that I need cation exchange membrane (CEM) to prevent Cl- from crossing over to the cathode. The only example of CEM that I ...
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How do you use the Nernst equation on lithium ion batteries [on hold]

Anode: LiC6<=> C6 + Li+ + 1e- Cathode: Li+ + 1e- + CoO2 <=> LiCoO2 Overall: LiC6+CoO2<=>C6+LiCoO2 How do you apply the Nernst equation to this reaction? The concentration of solids is ...
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1answer
152 views

What does the osmotic pressure do in an electrolytic solution?

I have learnt that in an electrochemical cell, the osmotic pressure in the solution hinders the flow of ions from the electrode to the solution, rather some ions may accumulate on the electrode ...
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1answer
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Do We change sign of electrode potential when reversing an equation?

I have a cell equation as: $$\ce{2Cr^0 + 3Cd^2+ -> 2Cr^3+ + 3Cd^0}$$ I am provided the standard reduction potentials as: $$\begin{align}\ce{Cd^2+ + 2e- &-> Cd} && E= \pu{-0.4V}\...
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what is the difference between oxidation state, charge and valency? [duplicate]

Is there any specific atom or compound or molecule possessing oxidation state different from charge and valency, so that we can clearly understand the difference between the three.
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What material is my pot and what is coating it please?

I have a large beaten metal pot I inherited from my parents. It was kept outside and entirely tarnished black, except for places in the inside which had a gold appearance (it's obviously not a gold ...
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Equilibrium constant kp or kc? [closed]

In electrochemistry , nerst equation we use logkc if chemical species are in solution form but if gases then we use logkp. But kp and kc are different emf of cell will come out to be different by ...
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Is this the right way to make a diy battery? [closed]

I know that batteries run off redox reactions. Therefore can I choose an arbitrary reduction reaction in one half cell, an arbitrary oxidation reaction that will happen at room temperature for the ...
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29 views

Is it possible to convert a combustion reaction directly into an electrochemical one?

I'm fairly inexperienced in chemistry so forgive me if this question is silly but, why is it not possible to convert a combustion reaction to an electrochemical one directly and harvest the electrical ...
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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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Will there be electrical conductivity when two platinum metal strips are connecting with hydrochloric acid? [closed]

In the following set-up, the bulb does not light up. Which of the following changes may light up the bulb? (1) Replacing platinum electrodes with silver electrodes (2) Replacing silver chloride powder ...
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1answer
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Positive electrode potential of copper

My book (NCERT India) says that the electrode potential of metals is decided by the following factors: Enthalpy of atomisation Ionisation enthalpy Hydration enthalpy It says that the first two ...
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1answer
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In the Nernst equation, does T refer to the temperature of the standard cell or the cell under non-standard conditions?

I am doing an experiment where I am varying the temperature of the electrolyte of the anode half cell. I am trying to calculate the cell potential using the Nernst equation under standard conditions ...
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Electrolytic cell to remove soft solder from silver?

Hi my chemistry is pretty dire but have vague idea that an electrochemical cell could be used to remove soft solder (lead/tin probably) from a piece of sterling silver in need of a repair. The ...
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1answer
2k views

Why does NaCl act as a catalyst for the reaction of CuSO4 + H2O + Al?

I am analyzing a reaction between water sulfate copper and aluminum. A chunk of $\ce{Al}$, e.g., aluminum foil. I realize that a layer of $\ce{Al2O3}$ forms on the surface of the $\ce{Al}$, ...
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1answer
42 views

Why do power requirement figures for water electrolysis on the web seem to be wrong?

I need to calculate the power needed to electrolyse 1 mole of water for a project. We will either use Polymer Electrolyte Membrane Electrolysis or Alkaline Water Electrolysis, they operate on 1.75V-2....
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1answer
47 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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Entropy of lead storage cell

I am having trouble with calculating the entropy of a lead storage cell. The standard cell potential is given as $\pu{2 V}$ and the standard enthalpy change is $\pu{-306 kJ}$. I found out the Gibbs ...
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1answer
53 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
1k views

Salinic bridges in voltaic cells

I'm doing a study a study on voltaic cells. I've been working with them for a while and one of the questions that I've had is how does the salt bridge affect the cell. I mean, I know it allows ions to ...
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2answers
163 views

Is there a potentiometric method for monitoring salt formation in organic solvent?

I work in a pharmaceutical R+D lab, and currently aim to develop a validatable potentiometric method for determining the optimal amount of acid to add to a basified small organic molecule for ...
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1answer
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Is it possible to generate electricity by using two inert electrodes in a galvanic cell?

The Daniell cell has two active electrodes, meaning that both the copper and the zink electrodes participate in the redox reaction. However, in a lemon battery for example, the copper electrode is ...
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1answer
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Calculating the standard reduction potential for the oxidation of water

I was working with Latimer and Frost diagrams for oxygen when I came across what seems to me a contradiction. From the Latimer diagram for oxygen below, we know the standard reduction potential for ...
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1answer
587 views

Adding Standard Reduction Potentials

I am working the following USNCO problem (#41 from 2002). Based on this question and answer Deriving a reduction potential from two other reduction potentials, it seems that $\Delta G$ must be ...
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1answer
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Half-Reactions of Hydroxide [closed]

The following is the equation I have: $$\ce{Ca(s) + 2H2O(l) -> Ca(OH)2 v + H2 ^}$$ I am tasked to write the half-reaction equations for both the oxidation and/or reduction process. So, currently ...
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1answer
584 views

How exactly does a battery work (specifically Pb/H2SO4/H2SO4/PbO2 lead acid battery)?

Specifically talking about the lead-acid battery, I understand (or think I understand) this much: The anode, in the presence of the electrolyte, $\ce{H2SO4}$ will be oxidised: $$\ce{Pb (s) + SO4^2- (...
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48k views

Which is anode and which is cathode?

A maybe (hopefully) simple question about the denotations of "anode" and "cathode". The below image is a schematic of a polymer solar cell from http://www.plasticphotovoltaics.org/lc/lc-...
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1answer
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Confusion about the relation between gibbs free energy and electromotive force

$$\Delta G = -nFE$$ My textbook says that we can measure that this $\Delta G$ is measured when the work is done reversibly. But my confusion is how will we work reversibly when we have an ...
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1answer
111 views

Does Intercalation and Deintercalation of Lithium ions occurs in Half Cell?

The important feature of Lithium ion batteries is the ability to intercalate and deintercalate lithium ions in anode and cathode . However when we use half cell, using lithium metal foil as anode, ...
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5answers
377k views

Positive or Negative Anode/Cathode in Electrolytic/Galvanic Cell

In a galvanic (voltaic) cell, the anode is considered negative and the cathode is considered positive. This seems reasonable as the anode is the source of electrons and cathode is where the electrons ...
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1answer
56 views

what should be the onset potential using cyclic voltammetry?

I am working for PEM fuel cell cathode material. I am confused regarding the onset potential determination for my catalyst (CV attached, fig 1 is complete CV while fig 2 is its zoom image for clear ...
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1answer
100 views

Why is the conjugate of a strong oxidizing agent a weak reducing agent?

I am a grade 12 student. While I was reviewing some electrochemistry, I had the following question. Take this reduction half-reaction: $$\ce{F2 (g) + 2e- <=> 2F- (aq) + $\pu{2.87V}$}$$ I know ...
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2answers
231 views

Why won't removing the salt bridge cause the battery to recharge?

If I understand correctly, the salt bridge in a battery is used to move positive ions towards the side that is becoming more negative, and negative ions towards the side that's becoming positively ...
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1answer
44 views

Can ZnO act as a reducing agent for noble metals like Pd?

Palladium ions (e.g., $\ce{Pd^2+}$) can be reduced to $\ce{Pd}$ by more reactive metals such as zinc. Metal oxides such as $\ce{ZnO}$ are very stable but can its atoms in the oxide structure still be ...
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1answer
92 views

Equivalent conductivity of barium chloride at infinite dilution

Find out the equivalent conductivity of barium chloride at infinite dilution given that the ionic conductivities of $\ce{Ba^{2+}, Cl-}$ are $\pu{127 ohm^-1 cm^2 equivalent^-1}, \pu{76 ohm^-1 cm^2 ...
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1answer
43 views

Current in a Lithium Ion Battery

I am trying to find the current transferred to the anode and cathode of a Lithium Ion Battery at different voltages. I know the temperature (approximately) of the battery, the battery's starting ...
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How does copper reduce dilute nitric acid to nitric oxide and concentrated nitric acid to nitrogen dioxide?

Here are the 2 equations: \begin{align} \ce{3Cu + 2NO3- + 8H+ &<=> 3Cu^2+ + 2NO + 4H2O} & E &= 0.62~\mathrm{V}\\ \ce{3Cu + 2NO3- + 4H+ &<=> 3Cu^2+ + 2NO2 + 2H2O}& E &...
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1answer
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In a galvanic cell where the two electrodes are in the same electrolyte solution, why do reduction and oxidation occur separately?

In a certain book, I was presented with the following solution: An iron nail is attached by a piece of wire to a magnesium ribbon, and the iron and magnesium are placed into the same container, with ...