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.

216 questions with no upvoted or accepted answers
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What exactly is an “electron-sponge”?

What exactly an "electron-sponge" [behavior/action/property/system] nickname is, and what makes a material an "electron-sponge" (preferably, quantitatively)? From what I found, it's typically a ...
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8k views

Oxidation of naphthalene with KMnO4

What is the product when naphthalene is oxidized by alkaline (or acidic) solutions of $\ce{KMnO4}$? Some possible reactions show up in a google search, but they have no references: Naphthalene to ...
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Are there acid/base processes in aqueous solution that are so slow that they are kinetically controlled?

This question came up in figuring out what the fundamental differences are between redox chemistry and acid/base chemistry (if any). In redox chemistry, strong oxidants and strong reductants can co-...
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Finding theoretical mechanism of sodium thiosulphate and hydrochloric acid

In class we conducted an experiment where we timed reactions between sodium thiosulphate and hydrochloric acid. We kept the concentration of the $\ce{HCl}$ constant, while changing the concentrations ...
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How to determine the iron content in spinach from a titration with permanganate solution?

I used titration to find the mass of iron in a $5~\mathrm{g}$ sample of spinach after leaving the spinach to soak in tap water for 5 different amount of times. I added $\ce{H2SO4}$ to the solution and ...
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328 views

Lemieux-Johnson oxidation on cycles

Consider 5-cyano-2,2-dimethylpentyl 4-methylbenzene-1-sulfonate: What would it yield by a Lemieux-Johonson oxydation ($\ce{OsO4}$, $\ce{NaIO4}$)? My first guess would have been that $\ce{OsO4}$ was ...
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906 views

What are the factors that affect the redox reactions?

In my work, I used $\ce{Co(OH)2}$ and $\ce{Ni(OH)2}$ as an active materials to fabricate as symmetric supercapacitors in which I used 1-butyl-1-methylpyrrolidinium dicyanamide as an electrolyte. From ...
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170 views

What makes “Color-Safe Bleach” color safe?

The ability of bleach ($\ce{NaOCl}$) to change the color of garments and introduce "bleach stains" is a well-known issue. In this question: Does bleach turn a substance white or colorless?, the ...
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4k views

Why does reduction of naphthalene with nickel/hydrogen lead to trans-decalin?

Is there any reason why $\ce{H2/Ni}$ leads to trans-decalin? I knew from high school that catalytic hydrogenations are always syn.
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Why do NaNO3 + Al + NaOH yield ammonia?

From Russian test problem 4301: $$\ce{3NaNO3 + 8Al + 5NaOH + 18H2O -> 8Na[Al(OH)4] + 3NH3(g)}$$ How does ammonia evolve here? Is it that we get hydrogen gas evolving in the reaction between Al ...
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277 views

Reduction of vanadyl ion

I want to reduce vanadyl to vanadium (III), can somebody please suggest some appropriate methods for it? I am trying to make a redox flow battery for a project but I have only vanadyl sulfate.
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After neutralizing a free radical, why don't anti-oxidants become free radicals themselves?

This is my understanding: A free radical is a molecule with a single unpaired electron. This molecule is highly reactive because it wants to steal an electron from another molecule (oxidation). Anti-...
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375 views

Reaction mechanism of thiol to disulfide oxidation under basic conditions?

I have been looking everywhere for an explanation to a reaction mechanism concerning the oxidation of DTT (or just thiols to disulfides in general) using oxygen as the oxidant. I'm aware that ...
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331 views

Mechanisms of Birch and Bouveault-Blanc Reductions

The question is all about the sequence of a possible Birch- and Bouvault-Blanc-Reduction in this exemplary substrate. With which reduction the mechanism begin? My first attempt was to classify the ...
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154 views

Rationalise the Relative Reactivity of Borane and DIBAL as Reductants

In Clayden's Organic Chemistry (Second Edition) it is written that borane is useful in chemoselectively reducing the most nucleophilic carbonyl to its corresponding alcohol. It is later said that ...
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72 views

Kinetics of nitric oxide production

Several articles affirm that NO can enhance the glutamate release from the presynaptic site; moreover, glutamate has been recognized as a major brain neurotransmitter and is considered to mediate ...
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215 views

Why does the electrolyte used in Lechlanché cell turn blue?

In my school there are jars which are turned into Lechlanché cells. Basically the cell has aqueous ammonium chloride solution as the electrolyte which is obviously transparent in the beginning. The ...
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613 views

Can oxidation of ethanol by copper(II) oxide yield copper(I) oxide as one of the products?

We know that ethanol is oxidised by copper(II) oxide to an aldehyde. Copper is reduced from $\ce{Cu^2+}$ to $\ce{Cu}$. Can this reaction, with some specific condition, yield $\ce{Cu2O}$ instead? That ...
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Comparing two oxidizing agents using electron configuration

Which oxidizing agent from the pair $\ce{K_2IrCl_6/K_2PtCl_6}$ is stronger? Explain your answer using their electron configurations. We write the electron configurations for $\ce{Ir/Ir^{4+}}$ and $\...
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572 views

Cobalt Oxalate / Potassium Permanganate Titration

My class just did a lab today where we mixed cobalt oxalate with $40~\mathrm{mL}$ of $\ce{H2SO4}$ and then titrated it with $\ce{KMnO4}$ (potassium permanganate). I need the mole ratio of cobalt ...
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142 views

Where do the rate laws for the Chlorine Dioxide-Iodine-Malonic Acid reaction come from?

After reading a section on this particular oscillatory reaction, something started bugging me about it. However, let me lay out the basis of my question. From what I've researched, Lengyel and ...
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1answer
3k views

Why do the pennies in the pre/post 1982 penny experiment sometimes dissolve completely?

USA pennies were nearly pure copper pre-1982. Post 1982 they are copper clad zinc. A common experiment in US high schools is to notch pennies with a file and add them to an HCl solution. The old ...
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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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429 views

Number of moles of acidified potassium dichromate required to liberate 6 moles of iodine from an aqueous solution of iodate ions

I came across this question in a recent exam I had taken: How many moles of acidified $\ce{K2Cr2O7}$ is required to liberate 6 moles of $\ce{I2}$ from an aqueous solution of $\ce{I-}$ ? So this is ...
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Can pheophytin be converted back to chlorophyll?

Some fossil leaves are "greenish" when first exposed but rapidly darken to an "olive brown" color when they come into contact with air. If the fossil leaf contains pheophytin, can the addition of ...
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68 views

Galvanic Cell Temperature Dependence

I'm currently studying the temperature dependence of the following cell: $\ce{Cu_{(s)} + 2Ag^{+}_{(aq)} <=> 2Ag_{(s)} + Cu^{2+}_{(aq)}}$ ($E^⦵ = \pu{+0.46 V}$) Experimentally, I recorded the ...
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55 views

Why is NOₓ conversion low at fuel rich conditions in a three-way catalytic converter?

$$ \begin{align} &\text{Oxidation:} &\quad \ce{2 CO + O2 &-> 2 CO2}\\ & & \ce{``HC" + O2 &-> CO2 + H2O}\\ & & & \\ &\text{Reduction:} &\quad \ce{2 CO +...
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73 views

Kinetic model of proton reduction

One of my colleagues is working on a homogeneous catalyst ($\ce{X}$) for proton reduction. The simplified proposed mechanism for it is the following. $$\ce{X + 2 e^- ->[$k_1$] X^{2-}} \tag{1}$$ ...
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432 views

Abnormal reaction of grignard reagent

My book states that: When isopropyl magnesium bromide is added to diisopropyl ketone, the expected tertiary alcohol is not obtained; instead the secondary alcohol; diisopropyl carbinol is obtained ...
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149 views

Why does standard reduction potential get multiplied by the change in oxidation state and not by the number of electrons transferred?

The whole basis of Frost diagrams is to have a graphical representation of the Gibbs free energy of formation ($\Delta{G}_{f}$) of different oxidation states of an element using the proportional ...
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597 views

How do thiol groups act as reducing agents?

In my biochemistry practicals, we used reducing agents such as beta mercaptoethanol: and dithiothreitol (DTT) Both of these have S-H groups, and I am sure that these are involved in the reduction ...
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240 views

Oxidation of alkenes and alkynes by Chromic Oxide?

As far as I know, $\ce{CrO3}$ doesn't effect the $\mathrm{\pi}$ bonds in an inert medium like pyridine. Would $\ce{CrO3}$ in acidic medium reduce alkynes to have the same products as acidified, warm $\...
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151 views

Do amino groups need to be protected during a Clemmensen reduction?

In class, we learned about the Clemmensen reduction of carbonyl groups to the corresponding hydrocarbon. This is all well and good, except that it would also seem that the conditions used in the ...
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746 views

Use of [H] to denote a reducing agent

In the reduction of an aldehyde (e.g. ethanal) to a primary alcohol, a reducing agent is needed: $$\ce{CH3CHO + 2[H] -> CH3CH2OH}$$ My book states that one hydrogen (the $\ce{H-}$ ion) is from the ...
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2k views

Why does ozone reduce to oxygen?

The O's in ozone and in dioxygen all have oxidation states of 0. If this is the case, why is ozone considered to be reduced to form dioxygen (since there's no change in oxidation state)? Would the ...
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199 views

Is it possible to react Rb + Al2O3?

I am wondering if the Rubidium ($\ce{Rb}$) in gas form can react naturally with Sapphire crystal ($\ce{Al2O3}$)? The temperature is $500\ \mathrm{K}$ and the pressure is around $1\ \mathrm{Pa}$ to $10\...
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Does Temperature Affect Rate of Reaction of Electrolytic Cell

I completed an electrolysis experiment. I used copper electrodes and a copper sulphate solution, and my independant variable was the temperature of the electrolyte. I was just wondering if increasing ...
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65 views

What is the voltage dependence of the thickness of oxide coating through anodising?

In titanium anodising, solid titanium reacts with the oxygen formed at it's surface (to form titanium(IV) oxide or $\ce{TiO2}$) through the electrolysis of water. Experimentation and research has ...
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619 views

Why does the OAc group leave in the first step of Oxymercuration?

The above picture shows the first step of Oxymercuration. The electrons attack the Mercury atom but the OAc group leaves. Why is this? Hg is a transition metal with a number of available oxidation ...
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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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39 views

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
102 views

How is indigo carmine used in Lowenthal-Permanganate titration as a redox indicator?

In a Lowenthal-Permanganate titration, cider tannins are quantified by titrating the cider with indigo carmine indicator and sulfuric acid against potassium permanganate. Tannins are antioxidants, so ...
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31 views

What is “protein redox conformation”?

From an article by Frye et al. [1]: Reduced glutathione (GSH) is the major intracellular redox buffer and is essential in free radical scavenging, redox homeostasis, maintenance of protein redox ...
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120 views

Effect of charge density on electrolysis of dilute sulphuric acid

I am told that if electrolysis of dilute sulfuric acid is performed under high charge density, then the following reaction takes place at anode instead of evolving oxygen: $$\ce{2 HSO4- -> H2S2O8 +...
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101 views

Possible side reactions in electrolysis of concentrated NaCl

This is a very basic question about which side reactions can take place if the electrodes are not shielded from each other during electrolysis of concentrated $\ce{NaCl}$. So, this is the desired net ...
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206 views

Colour of VO3^-?

To aquire the yellow colour of vanadium ion, it must be present in a 5+ oxdiation state. This can be acheived (according to my textbook) by adding dilute sulfuric acid to $\ce{NH4VO3}$, then followed ...
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15 views

Oxidative phosphorylation analogue

Does the salt bridge in galvanic cells resemble the ATP pump in the inner mitochondrial membrane? And if yes than did someone use this pH difference in harvesting this energy?
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24 views

Non-monotonic rank of oxidizing agents

"Which oxidizing agent is more powerful" seems to depend on what is getting oxidized. Consider for example oxygen vs chlorine. It is my understanding that chlorine is the more powerful agent for ...
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34 views

What's an appropriate ligand for Pd-Ag redox?

I want to reduce palladium with silver (in cellulose): $\ce{Pd^{2+} + 2Ag->2Ag+ +Pd}$. What is a good ligand and spectator ion for both metals? (The pH is not critical.) Ones I have considered: $\...

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