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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4
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2answers
800 views

Why is fluorine a oxidising agent? [closed]

An oxidizing agent pulls the electron cloud of the substance being oxidized towards itself, for example: $$\ce{F2 + 2 X- -> 2F- + X2}\qquad (\ce{X} = \ce{Cl}, \ce{Br}, \ce{I})$$ We also know that ...
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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
61 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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calculate the change in electrode potential when the activity of copper ions in solution is increased from 0.001 to 0.250 at a cu / cu2+ electrode [closed]

How does change in activity of copper ion in solution affect change in potential ? Increasing it from 0.001 to 0.250 makes a big difference and how do we calculate it ?
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Derivation of relationship between Gibbs free energy and electrochemical cell potential

Why is $\Delta G = -nFE$? I don't understand what the motivation is behind this definition. Was it derived or just given? The textbook provides no justification for this equation. In fact, much of ...
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0answers
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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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2answers
61 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 ...
7
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2answers
321 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
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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
355 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
49 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
59 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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2answers
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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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0answers
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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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2answers
1k views

Why is hypochlorite a stronger oxidizing agent than other oxychlorides?

The reduction potentials of perchlorate, chlorate, chlorous acid and chlorine dioxide in acidic and basic solutions are listed in the table below: $$ \begin{array}{lcc} \hline \text{Oxychloride} & ...
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3answers
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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 ...
6
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2answers
264 views

How to calculate the pH of a redox reaction between nickel(IV) oxide and silver?

For the following reaction: \begin{gather} \ce{NiO2(s) + 4 H+(aq) + 2 Ag(s) -> Ni^2+(aq) + 2H2O(l) + 2Ag+(aq)}\\ E^\circ = \pu{2.48 V} \end{gather} Calculate the $\mathrm{pH}$ of the solution if $E ...
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1answer
38 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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3answers
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Why is lithium the most reducing alkali metal, and not caesium?

Caesium has a larger size, and the effective nuclear charge that the valence electron experiences will be far less compared to that of lithium's, right? But lithium is still considered the strongest ...
3
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2answers
300 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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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
240 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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3answers
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What exactly is formed when K2Cr2O7 is reduced?

I read on Wikipedia and in many books that when $\ce{K2Cr2O7}$ is reduced, it forms $\ce{Cr^3+}$ and a change is noticed from orange color to green. I want to know in what exact complex/salt/compound $...
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1answer
29 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
114 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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1answer
85 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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Electrolysis of aqueous copper (II) nitrate

There are two copper blocks sitting in the $\ce{Cu(NO3)2 (aq)}$ solution, a battery is attached onto both of them, providing enough energy to start the reaction. Since solid pieces of copper are ...
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2answers
69 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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1answer
395 views

How to find the potential of a mixed Iron/ Cer solution?

Given the following half-reactions: \begin{align} \ce{Ce^{4+} + e^{−} &-> Ce^{3+}} & E° &= \pu{1.72 V}\\ \ce{Fe^{3+} + e^{−} &-> Fe^{2+}} & E° &= \pu{0.771 V}\\...
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1answer
12k views

Why is Cr²⁺ is a good reducing agent but Mn³⁺ is a good oxidising agent? [duplicate]

The question is the same as the title states. In my textbook,[NCERT Chemistry I for Class 12 , pg no 217.] the following is written $\ce{Cr^{2+}}$ gets converted to $\ce{Cr^{3+}}$ as the +3 oxidation ...
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4answers
290 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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2answers
108 views

In a half cell reaction, Is the potential halfed?

If you have an electrolyte of $\ce{Zn^2+}$ and $\ce{SO4^2-}$ (Neutral) Then you dip in it a Zinc electrode. Zinc potential is $\pu{-0.74 V}$ (relative to SHE). So that means there is a $\pu{-0.74V}$ ...
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1answer
41 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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0answers
46 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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0answers
18 views

What determines the potential of a half-cell with chemically inert electrode in a solution containing more than one redox pair?

Let's assume we have an electrode made of an inert metal as platinum or gold immersed in a complex mixture containing many compounds (in various concentrations) that can undergo redox reactions. We ...
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0answers
58 views

Blue bottle experiment turning yellow after being left alone

I conducted the blue bottle experiment, mixing glucose, sodium hydroxide and methylene blue and shaking to produce a blue colour, which turns colourless after a while due to the reduction of methylene ...
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2answers
1k views

Single electrode potential measurement

My textbook says that in a galvanic cell, it's not possible to measure single electrode potential independently. Instead, a Standard Hydrogen Electrode is used as the system is under equilibrium. Can ...
4
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1answer
176 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, ...
4
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1answer
180 views

How to identify which of two given electrodes with corresponding solutions is reducing more?

For the sake of the question, let’s assume that you are provided with two labelled rods of the pure metals $\ce{A}$ and $\ce{B}$ and two unlabelled bottles containing $\pu{1.0 mol dm-3}$ aqueous ...
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1answer
30 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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1answer
301 views

How do you calculate a half cell potential Copper(II) and Copper Sulfate?

I have to complete an experiment for school where I have copper and zinc electrodes placed into an electrolyte of copper sulfate and I have measured the potential across it at varying temperatures. ...
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0answers
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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
63 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
5k 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
87 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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0answers
50 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
110 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
83 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 ...
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1answer
35 views

In a galvanic cell,do charges accumulate on electrodes 1st (then redox occur) which produce E in the wire when we connect between electrodes? [closed]

We study that when we connect a wire between the terminals of a battery ,an electric field in established between terminals due to potential difference .Is the potential difference result of ...
2
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1answer
94 views

Latimer diagram for a metal in basic solution

Write the four half cell reactions from the Latimer diagram for a metal $(\ce{M})$ in basic solution. $$\ce{\overset{+6}{M}O4^2-(aq) ->[\pu{0.25 V}] \overset{+5}{M}O4^3-(aq) ->[\pu{0.55 V}] \...