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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Why do alpha-hydroxy ketones respond positively to Tollens', Fehling's, Benedict's, Schiff's and HgCl2 tests?
I learnt from a certain textbook that aldehydes and formic acid respond positively to Tollens', Fehling's, Benedict's, Schiff's and HgCl2 tests.
However, in another textbook I read that even alpha-...
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Why does the reaction of sodium nitrate, aluminium, and sodium hydroxide 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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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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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 five different lengths of times. I added $\ce{H2SO4}$ to the solution ...
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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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Oxygen tolerant RAFT polymerization using AIBN?
I want to do some RAFT polymerizations but don't have a nitrogen line at the moment. It seems that people have recently implemented oxygen scavenging strategies to enable open-air RAFT polymerization. ...
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Will charcoal (carbon) oxidize in the air?
Wikipedia — Carbon sequestration claims that burying charcoal into the soil offsets $\ce{CO2}$ and thus reduces the greenhouse effect:
In the soil, the biochar carbon is unavailable for oxidation to $...
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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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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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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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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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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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Can hydrogen peroxide dissolve rust?
WD-40's "help page" on "How To Loosen Rusty Bolts, Screws And Nuts" states:
Hydrogen peroxide can dissolve rust. Applying hydrogen peroxide to the
fasteners and letting it sit is ...
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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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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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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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Can hydrogen plasma reduce carbon dioxide?
There are several studies describing usage of hydrogen plasma to reduce metal oxides. This is not yet widely adopted in industry, but it is of interest for environmental reasons (such as described in ...
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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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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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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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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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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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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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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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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 doesn't the Nernst Equation match my data at low values of Q?
I have formatted my data below in a table so my issue is more clear and asked this question again, I apologize for any confusion. I don't understand why the low values of Q are inaccurate while the ...
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Why the change of the position of the salt bridge or metal piece leads to different voltage value?
I am doing an experiment where I use salt bridge to create galvanic cell. The goal of my experiment is to find if there is some correlation between the amount of solvent being used and the voltage ...
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Products formed on the reduction of KMnO4 in aqueous solution
The Latimer diagram for $\ce{MnO^-_4}$ is given below:
$$ \ce{MnO^{-}_4 ->[0.56V] MnO^{2-}_4 ->[2.26V] MnO_2 ->[0.95V] Mn^{3+} ->[1.51V] Mn^{2+} ->[-1.18V] Mn}$$
Then I have calculated ...
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What reaction does happen when molten sodium hydroxide reacts with aluminium?
The reaction between aqueous sodium hydroxide and aluminium follows this equation:
$$\ce{2NaOH + 2H2O + 2Al = 2NaAlO2 + 3H2}$$
But it's obviously not possible to balance this equation without the ...
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What products are formed when KMnO4 and KI react with each other in "weakly basic" medium?
While solving JEE Advanced 2020 (Paper 2) questions, I came across this particular question:
According to the final answer key, its answer is 6.
In my chemistry book (NCERT Chemistry), the following ...
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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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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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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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Why is NOₓ conversion low at fuel rich conditions in a three-way catalytic converter?
$$
\begin{align}
&\text{Oxidation:} &\quad \ce{2 CO + O2 &-> 2 CO2}\\
& & \ce{``HC" + O2 &-> CO2 + H2O}\\
& & & \\
&\text{Reduction:} &\quad \ce{2 CO +...
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What's an appropriate ligand for Pd-Ag redox?
I want to reduce palladium with silver (in cellulose): $\ce{Pd^{2+} + 2Ag->2Ag+ +Pd}$. What is a good ligand and spectator ion for both metals? (The pH is not critical.) Ones I have considered:
$\...
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Kinetic model of proton reduction
One of my colleagues is working on a homogeneous catalyst ($\ce{X}$) for proton reduction. The simplified proposed mechanism for it is the following.
$$\ce{X + 2 e^- ->[$k_1$] X^{2-}} \tag{1}$$
...
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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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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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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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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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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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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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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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Reaction of chlorine with hot/cold solution of hydroxide
When chlorine reacts with cold solution of say potasium hydroxide, the disproportionation goes to lower oxidation states:
$\ce{Cl2 + 2 KOH -> KCl + KClO + H2O} $
Whilst with hot solution the ...
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What is the easiest way to concentrate a solution without causing it to hydrolyze?
I’ve been working with iron acetate solutions in dilute acetic acid (vinegar) and I’ve been running into a problem. Every time I try to boil off the solvent the solution hydrolyzes to form iron oxides....