Questions tagged [redox]

Redox is the portmanteau of reduction and oxidation. This tag should be used in questions where both the reduction and the oxidation process are under focus. This tag is not limited to inorganic chemistry. If the question is specifically about either reduction or oxidation (not both) of an organic compound, use [organic-reduction] or [organic-oxidation] instead.

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362 views

Are aqueous solutions of oxidizing agents safe? [closed]

In the "reducing agent" article in Wikipedia it says Good reducing agents are reagents that deliver $\ce{H2}$. Wouldn't that make water unsafe to dissolve oxidizing agents?
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What does onset of oxidation mean in Cyclic volammetry

I've read a few posts on here on how to calculate onset of oxidations in Cyclic voltammetry. However, I dont know what it actually means when comparing the onsets of oxidations of two different ...
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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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Why is bleaching with chlorine permanent but with sulphur dioxide temporary?

I was reading the properties of chlorine when I came across this statement: Chlorine is a powerful bleaching agent; bleaching action is due to oxidation. Chlorine bleaches vegetable or organic matter ...
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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
85 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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2answers
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Confusion regarding $\delta$ charge compared with electronegativity

I heard on a lecture of an online site that, let us say, we have two orbitals (1 and 2). Now, it will be like a spherical cloud. Now, what they say is that Now, we can notice that for orbital number ...
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2answers
161 views

Does increasing one of the electrolytes in a galvanic cell increase the voltage?

I would like to know how you could increase the voltage in zinc and copper galvanic cell: $$\ce{Zn(s) + Cu^2+ → Zn^2+ + Cu(s)}$$ I know that temperature and surface area is a factor that affects the ...
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Can we balance a redox reaction in basic medium just like as acidic medium and add OH- ions on both sides to cancel out H+ Ions? [closed]

My teacher told me that the method (which I mentioned above) is wrong but I find many references of saying the same method correct.
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While electrolyzing concentrated aqueous sodium chloride, why is it that chlorine is discharged but not sodium?

Hydrogen and hydroxide both exceed sodium and chlorine in terms of reduction and oxidation potential respectively. While electrolyzing a concentrated solution of aqueous NaCl, it is known that ...
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1answer
95 views

Reduction of alcohol to alkane [closed]

I have been looking everywhere for hours now, and can't find anything on a simple lab reduction of an alcohol to an alkane that doesn't involve any "fancy" reagents such as tosylates, metal ...
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Will changing the salt in the salt bridge change the voltage produced in a galvanic cell?

I have used zinc sulfate and copper sulfate as the solutions, and used zinc and copper electrodes. For salt bridge I took lithium, potassium, calcium, sodium and zinc nitrates. The results are as ...
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Out of KCl, CaCl2, MgCl2, NaCl, which causes the greatest corrosion rate of iron and why?

I know that salts act as an electrolyte in a redox process and rusting of iron, where iron loses electrons and oxidizes, and oxygen gains electrons and reduces. I did an experiment with KCl, NaCl, ...
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What is the n factor of h2o2 undergoing disproportionation reaction liberating oxygen [closed]

There is a lot of confusion about the n-factor of hydrogen peroxide in its disproportionation into water and oxygen. $$\ce{2H2O2 -> 2H2O + O2}$$ Some sources(1,2) say n-factor of $\ce{H2O2}$ is 2 ...
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1answer
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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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1answer
517 views

How does precipitate affect cell potential?

A cell is set up with copper and lead electrodes in contact with $\ce{CuSO4(aq)}$ and $\ce{Pb(NO3)2(aq)},$ respectively, at $\pu{25 °C}.$ The standard reduction potentials are: $$ \begin{align} \ce{Pb^...
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1answer
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What happens at the inert anode in an electrolytic cell? [duplicate]

Recently I did an experiment using graphite as the anode and iron as the cathode for an electrolytic cell. I tried plating different metals such as copper, nickel, and zinc with CuSO4, NiSO4, and ...
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1answer
85 views

Thinking of reducing aluminum hydroxide with magnesium

Is it possible to reduce aluminum hydroxide to aluminum metal by using a sacrificial magnesium electrode in a single displacement reaction? I checked my revision of redox charts and it looks like it ...
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2answers
308 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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In dative bond S→ S, why are the Oxidation state of donor S = +2 and recipient S= -2 although both of them have the same electronegativity?

We know that if the dative bond is directed towards less electronegative element, it is ignored while calculating the oxidations state and it is considered as +2 for donor and -2 for the recipient ...
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2answers
85 views

What do ε₀ and V mean in a Pourbaix diagram?

From Wikipedia: What does this graph mean? What is $\varepsilon$? It looks like $\varepsilon_0$, like the vacuum permittivity, but what does this have to do with the polymorph and/or isomers of ...
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2answers
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How is it determined how many electrons are transferred in redox reactions?

For example, iron and tin(II) sulfate will react to produce iron(II) sulfate and tin: $\ce{Fe + SnSO4 -> FeSO4 + Sn}$ With the following half equations: $\ce{Fe + SO4^{2-} -> FeSO4 + 2e-}$ ...
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1answer
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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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2answers
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Why does a chemical have more than one oxidation number?

Like for group I metals, it is understood that all the elements in the group would have an oxidation number of +1. As far as I know, oxidation number is how much electron the element loses/gains. ...
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What reaction is used for calculating pH of the solution obtained after ethanol oxidation with potassium permanganate?

If $\pu{30.0 ml}$ of $\pu{0.20 M}$ ethanol solution reacts with $\pu{1.80 g}$ potassium permanganate, what will be the final $\mathrm{pH}$ of the solution? Assume a complete reaction and that only the ...
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How efficient is Zinc Acetate as an Oxygen absorber?

I used to work in a microbiology lab and they used zinc acetate as O2 absorber for the anaerobic chamber. Was this an efficient way to scrub O2 from the air? I am asking because I want to make an N2 ...
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1answer
35 views

Why do we need weak or strong acids to displace the anions of other weak acids from salts?

I have already looked at Why does a strong acid displace salt of weak acid? but I couldn't understand the answer and the analogy there. And I mean the above question in the following context : $\ce{...
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4answers
358k views

Why is it important to use a salt bridge in a voltaic cell? Can a wire be used?

I was learning about voltaic cells and came across salt bridges. If the purpose of the salt bridge is only to move electrons from an electrolyte solution to the other, then why can I not use a wire? ...
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2answers
992 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
78 views

Balancing complex redox reaction of gold treated with sodium cyanide

How would you balance this reaction: $$\ce{Au(s) + NaCN(aq) + O2(g) + H2O(l)-> Na[Au(CN)2](aq) + NaOH(aq)}?$$ Here’s what I’m came up with. First we can balance any atoms besides hydrogen and ...
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1answer
77 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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1answer
4k views

Does the Clemmensen reduction reduce the C=C bond of α,β-unsaturated ketones?

The Clemmensen reduction is a chemical reaction which reduce aldehydes and ketones to alkanes. In my book, it is written that under such conditions, double and triple bonds are not reduced, but my ...
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2answers
81 views

How do I prevent oxygen interfering when I prepare a FeCl2 solution from anhydrous FeCl2 powder?

I have a bottle of anhydrous $\ce{FeCl2}$ powder (from here; it is 98% pure and was kept in a glovebox after opening it for the first time to minimize reactions with oxygen) and want to make this into ...
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1answer
712 views

Why isn't my electrochemical cell producing its potential voltage

For a school project, I am testing how concentration affects the voltage output of three metals. So I am building voltaic cells with 0.1 M copper nitrate and 0.1 M, 0.01 M, and 0.001 M of zinc, ...
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71 views

Elimination vs reduction reactions - how to tell

Here are two compounds: Compound H: and compound I: Compound H reactions with the reagent shown below to form compound I and two other products. How would you clarify this reaction? I thought it was ...
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1answer
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Difference in the functioning of alkaline and acidified KMnO4

What is the difference in the functioning of alkaline and acidified $\ce{KMnO4}$ as a reagent in organic chemistry? E.g., in the oxidation of a primary alcohol to carboxylic acid, we use acidified $\...
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2answers
160 views

How does increasing the Hydrogen Concentration of CuSO4 (electrolyte) affect electroplating of copper

I'm trying to find an answer as to how lowering the pH of the CuSO4 solution during electroplating of copper affects the amount of copper deposited onto the cathode. My very basic understanding is ...
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2answers
348 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 doesn't NASA or SpaceX use ozone as an oxidizer for rocket fuels?

Presumably, it would be expensive to use ozone ($\ce{O3}$) as an oxidizer instead of $\ce{O2}$, but would the extra oomph be worth it? Does $\ce{O2}$ provide as much thrust/energy/heat as can be ...
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1answer
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What are the practical differences between the various DMSO oxidations (Swern, etc.)?

Recently, I was reading a paper about a total synthesis of (+)-rubriflordilactone A (the article is open access: Angew. Chem. Int. Ed. 2015, 54 (43), 12618–12621). In two different steps where an ...
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1answer
101 views

Acidic KMnO4 oxidizes H2S to S. Why doesn't the oxidation proceed further to sulfur oxide, sulfur dioxide or sulfur trioxide?

I have some idea about the question. I think it has to do with oxidation/reduction potentials but I am not able to find any resource for the exact values or how to make sense of them in this context. ...
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2answers
229 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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2answers
1k views

What are high-energy electrons?

I read that (in cellular respiration) the transported electrons in NADH have a higher energy than those in FADH2. I can't find a (simple or otherwise) explanation of what a "high-energy" ...
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1answer
50 views

Conditions for spontaneity of redox reaction among redox couples with equal standard reduction potentials

A question from the university course: Could a redox reaction spontaneously occur among the redox couples $\ce{A_{ox}}/\ce{A_{red}}$ and $\ce{B_{ox}}/\ce{B_{red}}$ within non-standard circumstances ...
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4answers
1k views

In NaCl electrolysis, why does chlorine ion get oxidized but not oxygen ion? [closed]

In $\ce{NaCl}$ electrolysis, on the positive electrode (aka. on the electrode where oxidation happens), $\ce{Cl-}$ ions are oxidized to $\ce{Cl2}$. But why don't we see any $\ce{O^2-}$ (naturally ...
2
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1answer
96 views

Lost track of the hydrogen in step 3 of the Krebs cycle

I'm trying to follow the Krebs cycle step by step, accounting for the number of hydrogens in each molecule before and after reactions. I've run into a problem starting from step 3. Isocitrate has ...
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0answers
99 views

Which of the following is the strongest oxidizing agent?

Which of the following is the strongest oxidizing agent? A) $\ce{I2}$ B) $\ce{Ag^2+}$ C) $\ce{Cu^2+}$ The answer is apparently B) but I think it has to be A) because it is the only non-metal which ...
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1answer
48 views

Balancing redox equation involving ethanol and dichromate ion [closed]

$$\ce{C2H6O(l) + Cr2O7^{2-}(aq) -> C2H4O2(aq) + Cr^3+(aq)}$$ Basically, I have written the half equations, but I have having trouble with converting ethanol to acetic acid ($\ce{C2H6O -> C2H4O2}$...
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34 views

Driving force of Galvanic cell

Work can be extracted from galvanic cell which has a negative Gibb's free energy. I was wondering what is the driving force of it: I would naturally think its the Gibb's free energy, but the gaps ...

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