Questions tagged [reduction-potential]

For questions about the reduction potential (A measure of the tendency of a chemical species to acquire electrons and thereby be reduced) or its applications. Also see the tag [electrochemistry].

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31 views

Oxidizing properties of sulfuric acid: can it oxidize hydrochloric acid to chlorine?

Can $\ce{H2SO4}$ oxidize $\ce{HCl}$ to $\ce{Cl2}$? I know that $\ce{KMnO4}$ can do it, but my question is considering $\ce{H2SO4}$. In sulfuric acid, sulphur is in +6 oxidation state and in $\ce{KMnO4}...
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29 views

How to write the Nernst Equation for this reaction?

I am required to write the Nernst equation for the following reaction: $\ce{O_2 + 4H^+ + 4e^- -> 2H_2O}$ Clearly, here $\ce{O_2}$ is getting reduced from an oxidation number of zero to an ...
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1answer
65 views

Which Half-Reaction to Use? [closed]

I was hoping for some help with choosing half-reactions for an electrolytic cell. This was the problem that sparked the question (Question #6 from the 2020 USNCO Part II): The correct answer is $$2\...
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23 views

Is it the solution energy or the reduction potentials (or both) that drives a galvanic cell?

I have received conflicting explanations for why the redox reaction in a galvanic cell occurs. Explanation 1: Some say that it occurs because the anodic metal dissolves more easily than the cathodic ...
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59 views

Reaction of Copper and concentrated sulphuric acid

We know that dilute $\ce{ H2SO4}$ doesn't react with copper because copper has higher reduction potential ($0.33$) as compared to hydrogen ($0.00$). However, it reacts with conc. $\ce{H2SO4}$ and ...
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42 views

What is the difference between these notations and terms?

I can't tell if they're being used interchangeably or if there's some nuanced difference betweem them. Here they are: $E^∘$ $E_0$ $E_h$ $E^⦵$ If I understand correctly, electrode potential is the same ...
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3answers
80 views

Does a change in oxidation number in a redox reaction mean that an actual electron transfer occured?

Oxidation numbers are fictitious charges that pretend the entire molecule is an ion i.e. it artificially localizes electrons onto atoms within a single molecule. In a redox reaction, we find that an ...
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18 views

Can you calculate the oxidation potential of an ion?

Is there any way to calculate the oxidation potential of [Fe(OH)(H2O)5]+? I am unsure if it can be done since I have only seen oxidation potentials provided for specific reactions of single elements, ...
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14 views

How to use anodic and cathodic overpotentials to calculate electrolytic energy efficiency?

I am trying to calculate the energy efficiency for $\ce{CO2}$ reduction to formate, coupled to water oxidation based on literature data. $$\ce{CO2 + 2e- + 2H+ -> HCOOH}$$ $$\ce{H2O -> 2H+ + 1/...
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How can I convert cathodic energy efficiency to overall energy efficiency?

Im working on calculation which involve the energy efficiency of producing formate by CO2 electroreduction. I wonder how to convert the reported cathodic energy efficiency (71%) of papers e.g (1) this ...
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22 views

How to calculate Energy Efficiency of electrochemical production

I'm trying to understand some basic electrochemistry as a non chemist and struggling to find the info online effectively. Its clear that energy efficiency = Energy(useful) / Energy (input). So, I know ...
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34 views

Understanding Pourbaix diagram

I am recently taking courses in environmental chemistry and I was introduced to Pourbaix diagram. I was taught that the lines in the Pourbaix diagrams are equilibrium lines. Lets take as an example ...
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1answer
64 views

Can water oxidize zinc?

According to this textbook, H₂O has lower reduction potential (-0.83 V) than Zn (-0.76 V). This mean zinc is unable to reduce water to hydroxide. If so, why this video demonstrate that by heating zinc ...
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1answer
39 views

Electrochemistry - reduction potentials - an IB Chemistry Question [closed]

I have re-read the Electrochemistry chapter from my textbook just now to remind my self of the exact formulae. I still don't understand how to approach this question, however - how can we work it out? ...
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32 views

Could Carbon Monoxide be reduced by oxidising a more reactive metal?

After studying displacement at school, I wondered if it is possible to reduce the toxic gas of carbon monoxide to less harmful and more useful substances, like so: Carbon monoxide + metal -> Carbon ...
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1answer
95 views

calculate cell potential for the voltaic cell where its involving the two cobalt species with Copper

Calculate the cell potential for the voltaic cell that results when the following two half-cells are connected at $\pu{25 ^\circ C}$: (1) A platinum electrode inserted into a solution of $\pu{0.10 M}$ ...
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2answers
218 views

Origin of electrode potential and its connection with electric double layer

Recently, I was learning about electrode processes and I came across the topic of "electrode potentials". I understood that at equilibrium, a potential difference was generated at the ...
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1answer
37 views

Do I have to systematically show the protons in my reaction equation to find the Pourbaix diagram's line equations?

I was trying to get the line equation for the Pourbaix diagram for the couple $\ce{Ni(OH)2}/\ce{Ni}.$ I can write two chemical equations for basic and acidic conditions, respectively: $$ \begin{align} ...
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1answer
87 views

EMF - Intensive or Extensive Property

In electrochemistry, I know that standard emf of a cell (also called standard electrode potential (E°)) is an intensive property. But, I wanted to know whether non-standard emf will also be intensive ...
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64 views

Why do nitrogen-containing organic compounds give N2 as the combustion product?

My teacher gave the explanation stating that consider that first the nitrogen in lower state is oxidised to $\ce{N2}$ and then the further oxidation would stop as the $\ce{N-N}$ bond energy of $\ce{N2}...
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1answer
72 views

What does the salt actually do during electrolysis?

Pure water does not conduct electricity. When you dissolve a salt like $\ce{Na2SO4}$ in water the solution becomes a better conductor. If electrolysis is done on this solution, oxygen and hydrogen ...
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72 views

Nernst equations for the reduction of sulfate(IV) and nitrate(V) anions

Write a Nernst equation $(\pu{25 °C})$ for system: $$\ce{SO3^2- + 3 H2O + 6 e- -> S^2- + 6 OH-}\tag{R1}$$ and system: $$\ce{NO3- + 3 H+ + 2 e- -> HNO2 + H2O}\tag{R2}$$ I am not really sure if ...
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82 views

How to measure chlorine content using ORP sensor?

In my project I need to measure pH, turbidity, and chlorine level of treated drinking water. I found sensors for measuring pH, turbidity, and also chlorine. The actual problem begins is that the cost ...
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2answers
335 views

How to refine manganese metal from manganese(IV) oxide found in batteries? [closed]

I opened up some lantern batteries, and inside there's $\ce{MnO2}$ powder, carbon rods, and zinc casings, and other stuff that I don't know what it is exactly. I scraped out $\ce{MnO2}$-containing ...
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2answers
177 views

Why can't nitrate ion in aluminium nitrate solution oxidise copper when a copper spoon is used to stir the solution?

I have been recently studying electrochemistry and I came across the electrochemical series. A question was asked saying what will happen if a copper spoon is used to stir an aluminium nitrate ...
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1answer
84 views

Are the potentials of the electrolytes equal in Galvanic cell?

My book defines Electrode Potential for a Galvanic Cell as follows: A potential difference that develops between the electrode and the electrolyte is called Electrode Potential $$E= V_{electrode} - ...
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1answer
113 views

Why can't iodide be oxidised to iodate in acidic medium?

Even if we use a strong oxidising agent like 'permanganate ion in acidic medium' it doesn't help oxidise iodide to iodate, but a relatively weaker oxidising agent 'permanganate ion in alkaline medium' ...
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How to control the potential of an electrode?

I Have been reading about redox potential and Nernst equation. However, I got the understanding that the potential for the material is fixed (excluding Temperature). My Problem: I have two electrodes ...
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3k views

Can carbon dioxide be reduced to carbon monoxide and oxygen to produce energy?

There are lots of questions about reducing or burning CO2 to carbon and oxygen to solve climate change, but of course that wouldn't work because it takes a lot of energy. But carbon monoxide is more ...
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1answer
41 views

Reduction by Activated Carbon

Does reduction by carbon itself occur when filtration is performed using activated carbon? Is it part of the central mechanisms involved in activated carbon filtration? One of the specificities of all ...
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50 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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2answers
279 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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1answer
33 views

Metal deposition on passing electricity [closed]

A question asks about the results on electrolysis involving metals, and the answer says that Mg and Al would be deposited on the cathode. Aren't their reduction potentials lower than that of water? ...
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1answer
162 views

What is the number of electrons being transferred in electrolysis of aluminum oxide? [closed]

$$\ce{ 2/3 Al2O3 -> 4/3 Al +O2}$$ As we know, to find the Gibbs free energy, we need to use this formula: $$ G= -nFE^\circ$$ What would $n$ be in this case? After breaking it down into the half ...
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2answers
82 views

Is HBrO2 a reductor?

I'm working on a chemistry project and that features a reaction where $\ce{Br-}$ participates in a redox reaction as a reductor. Eventually, $\ce{HBrO2}$ competes with $\ce{Br-}$ to react with the ...
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2answers
662 views

How does overvoltage affect the products of electrolysis?

When you electrolyse an aqueous solution of $\ce{NaCl},$ the product formed at cathode is $\ce{H2}$ gas (preferential discharging), but the product formed at anode is $\ce{Cl2}$ gas. According to ...
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4answers
630 views

What happens when a piece of copper is placed in 1M HCl?

I know that the answer is that nothing happens, but the explanation is confusing me in some places. Firstly, we are given that: \begin{align} \ce{Cl2 + 2e- &-> 2Cl-} & (E &= \pu{1.36 V})...
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1answer
44 views

How do you work out whether reduction would occur based on reduction potentials [closed]

I'm having a bit of trouble with standard reduction potentials. Specifically, when you're given a table of half reactions and reduction potentials...is the potential of the reverse reaction (the ...
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1answer
194 views

Nernst equation and equilibrium

I am currently stuyding electrochemistry, and recently I've stumbled upon a problem where one is supposed to calculate the concentration of Fe3+ ions after a solution containing Fe2+ was titrated ...
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59 views

Log(Q) is zero, therefore the effect of temperature change is unaccounted for by Nernst Equation?

I have an internal assessment on Nernst Equation. The experiment is seeing how changing temperature effects cell potential. The solution are zinc and copper sulfate with each having concentration of ...
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1answer
234 views

Subtracting standard electrode potentials

As far as I'm aware, if we construct a half cell ($\ce{A + e- <=> A-}$) under standard conditions then the standard electrode potential $E^⦵$ is the potential of the $A/A^{+}$ couple wrt. SHE, ...
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1answer
33 views

Effect of reduction potential on particle size of chemically precipitated silver particles [duplicate]

Is there no mathematical relationship between redox potential and particle size saying that an $X$ potential should yield a $Y$ particle size? Right now its general that large redox potential results ...
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2answers
104 views

Can the 5+ and 4+ oxidation state of Vanadium ion exist independently?

From my class text book: The oxidation states of Vanadium ions 5+ and 4+ are shown in the compounds $\ce{VO2^{+}}$ and $\ce{VO^{2+}}$ respectively, whereas $\ce{V^{3+}}$ and $\ce{V^{2+}}$ are ...
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25 views

Stability of cuprous iodide in aqueous solution

An aqueous solution of $\ce{Cu+}$ is usually unstable, but $\ce{CuI}$ is stable. Explain. $E^\circ(\ce{Cu^2+/Cu+}) = \pu{0.153 V}$ and $E^\circ(\ce{Cu+/Cu}) = \pu{0.521 V}.$ I found this question ...
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3answers
66 views

Is redox potential a valid term? [closed]

I mean doesn't every compound has its own different reduction and oxidation potential ? Or its just one potential that can be compared to understand which one will get reduced and which one will get ...
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1answer
774 views

What is the role of hydration enthalpy in oxidation?

My textbook says that the greater oxidising behavior of fluorine than chlorine can be attributed to the high hydration enthalpy of $\ce{F-}$ ions and the low dissociation enthalpy of $\ce{F-F}$ bond. ...
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1answer
115 views

Reduction potential as a function of pH

I have read that Latimer diagrams can be represented both in an acidic medium (pH = 0) and in a basic medium (pH = 14). I would like to know how to calculate the reduction potentials as a function of ...
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57 views

Help understanding Electrochemistry diagram

I was reading some literature when i came across the following figure and was wondering if someone could help explain it to me. I see on the vertical axis it is potential vs Li/Li+ and see that Oxides ...
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1answer
161 views

Isolating barium(II), copper(II) and zinc(II) from aqueous solution [closed]

Q15 Each metallic ion was separated from an aqueous solution containing $\ce{Ba^2+},$ $\ce{Cu^2+},$ and $\ce{Zn^2+}$ by the procedure shown in the following figure. From ①–⑥ in the table below choose ...
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1answer
104 views

Question About Reversible Reactions and Batteries

So my book says that the batteries we have considered so far( Daniell cells) are low life span, because they reach equilibrium too fast. In the next paragraph, it says they are also made by ...