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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NAD+ and NADH /H+
The $\ce{NAD^+}$ molecule has an electron-poor carbon susceptible to a nucleophilic attack by a hydride ion: It's the C4 of the pyridine ring, who loses its aromaticity in this way.
Usually, it is ...
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How to balance iodometric equations using ion electron method? [duplicate]
I found out the reductant, oxidant, oxidation half reaction, reduction half reaction; balanced ions (adding $\ce{H2O},$ $\ce{H+},$ electrons) and charges:
$$\ce{K\overset{-1}{I} + \overset{+2}{Cu}SO4 -...
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Reaction of lead with acetic acid and hydrogen peroxide solution
My textbook says lead reacts with acetic acid when there is enough oxygen to oxidize lead:
$$\ce{2 Pb + O2 + 4 CH3COOH -> 2 Pb(CH3COO)2 + 2 H2O}$$
So, I added lead into mixed solution of acetic ...
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The difference between Zn and Al on acid and base reaction
Because it was written on my textbook that Zn and Al dissolves in acid and alkali, I tried.
When I put Al in NaOH solution it reacted immediately. But when I put Zn in the same concentration of NaOH ...
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Why doesn't hydrochloric acid oxidize tin to tin(IV) chloride?
Diluted hydrochloric acid oxidizes tin to $\ce{Sn^2+}$ ion:
$$\ce{Sn + HCl(aq) -> SnCl2(aq) + H2(g)}$$
Why is oxidation not complete? $\ce{Sn^4+}$ has closed shell and is more stable.
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What do you think is happening to aluminium in salt water with rusted copper?
I put some aluminium foil and rusted copper(namely a Japanese 10 yen coin) in saturated NaCl solution.
After some minutes tiny amount of small bubbles were observed on the surface of the foil.
After ...
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Reaction of hydrogen peroxide with acetic acid and potassium permanganate
I conducted an experiment where I mixed hydrogen peroxide $\ce{H2O2}$, acetic acid $\ce{CH3COOH}$ and potassium permanganate $\ce{KMnO4}$ under vigorous stirring. The reaction hasn't stopped after 15 ...
user127378
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Conditions for Pd/C reduction of alkene
I am trying to do a $\ce{H2}$ reduction of cyclic alkene (otherwise simple hydrocarbon with 1 methyl group along with the chain about the weakly-strained cycle) using $\ce{Pd/C}$, the cycloalkene ...
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How does xenon react with O₂F₂?
This reaction was asked in my college entrance exam. I searched through the entire Internet, but I couldn't find any papers/sources.
I suspect since O₂F₂ is a strong fluorinating agent, one of the ...
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Stoichiometric coefficients in reaction between vanadium(II) oxide and iron(III) oxide
Calculate the weight of $\ce{V2O5}$ produced from $\pu{2g}$ of $\ce{VO}$ and $\pu{5.75 g}$ of $\ce{Fe2O3}$
Now we write the reaction as following - $$\ce{2 VO + 3Fe2O3-> V2O5 + 6FeO}$$
Now, by the ...
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Can you oxidize gold using only oxygen?
I keep reading that gold does not react with oxygen, but I also see information about gold Oxides (ie: aurous oxide, Au2O and auric oxide, Au2O3)
Knowing that there is a way of getting gold oxide ...
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Calculating half-cell potential from two reduction potentials [duplicate]
It is sometimes necessary to compute E° for a given half reaction from other half reaction of known E°.
For example, the standard electrode potential for the oxidation of Titanium metal to Ti³⁺ can be ...
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Mechanism of the blue bottle experiment
I have researched multiple mechanisms for this experiment yet all of them suggest different versions or are too vague. None of them are consistent since the final overall equation seems to be missing ...
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Reaction of copper(II) chloride and aluminium foil
So I did an experiment recently with copper(II) chloride and aluminum. As they reacted with each other the redox reaction made the aluminum a brown substance that is supposed to be copper and the ...
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What drives double displacement reactions?
I have two questions:
I understand that in a displacement reaction the more reactive element displace the less reactive element. But why? In the reaction with Zinc and Copper Sulfate, we form Copper ...
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Would this redox titration be possible as a direct titration rather than a pseudo-back titration?
In a general chemistry lab protocol (green chemistry, ISBN-13: 978-1482230208), students determine the content of ascorbic acid in a vitamin C tablet. There is an ascorbic acid standard in a buret, ...
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Equivalence point in relation with law of equivalence
Why is that we apply law of equivalence only at equivalence point during a titration. Isn't the law valid always? In the sense, cant we use law equivalence even before we reach the equivalence point?
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Should change in enthalpy be zero in galvanic cells?
When an exothermic redox reaction happens by just mixing the reagents, the change in enthalpy at constant pressure equals heat which is consistent with the fact that:
For a closed system at constant ...
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Oxidation Reactions/Reactivity of Manganese Metal in Air and Water
I am planning on doing some reactions that lead to Manganese metal and a neutral solution containing $\ce{Mn^{2+}}$ as by-products, and I wanted to try some things out with the Manganese as well.
...
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Why do we sometimes change the sign for standard electrode potentials?
Question:
In this cell, the copper is oxidized and $E_{cell} = \pu{+1.15 V}$.
$$\begin{align}
\ce{Cu^2+(aq) + 2e− -> Cu(s)} & &(E &= \pu{+0.34 V})\\
\ce{Mn^3+(aq) + e− -> Mn^2+(aq)} ...
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How do you determine the charge of the metal ion in a single replacement reaction? [closed]
Say we have a simple single replacement reaction between a salt and a metal
$$\ce{2 AgNO3 + Cu -> Cu(NO3)2 + 2 Ag}$$
We know in normal circumstances, silver always has a $+1$ charge, and in normal ...
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Does the reaction of solid Sodium Chlorate and Hydrochloric acid generate Chlorine Dioxide?
I did this reaction on a very small scale, swirled it around to mix and react, and saw a yellow green gas come out, as Chlorine gas is one of the products. However, based on what I found online about ...
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Why chlorate(V) is one of the primary products of disproportionation reaction between chlorine gas and hot concentrated NaOH?
Cold diluted $\ce{NaOH}$ reacts with $\ce{Cl2}$ producing hypochlorite:
$$\ce{2 NaOH(aq, dil, cold) + Cl2(g) -> NaClO(aq) + NaCl(aq) + H2O(l)},\tag{R1}$$
whereas hot concentrated $\ce{NaOH}$ yields ...
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Reduction potential of water [closed]
I can't understand what is meant by the reduction potential of water. In Electrolysis of water decomposition of water takes place as a result of which
$H+$ and $OH-$ are furnished. They migrate ...
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How does the redox reaction in a voltaic battery pile start?
From the Wikipedia article, the redox reaction for a voltaic pile is:
\begin{align}
\text{Oxidation:} && \ce{Zn &-> Zn^{2+} + 2e^-}\\
\text{Reduction:} && \ce{2H^+ + 2e^- &-&...
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What is the black sticky residue after heating copper hypophosphite?
I am experimenting with double sided PCB (printed circuit board) via (connections from one side to the other) holes activation.
The activation is the process of making the walls of holes electrically ...
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How is 1 mole hypochlorite ion equivalent to 1 mole chlorine gas?
According to my book, 1 mole ClO- is equivalent to 1 mole Cl2. How is that even possible? 1 mole ClO- contains 1 mole Cl atoms. On the contrary, 1 mole Cl2 gas contains 2 mole Cl atoms. So, how are ...
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Should I write formula for oxalate or oxalic acid while balancing a redox reaction using the ion-electron method?
Problem:
Balance the following reaction using the ion-electron method:
$$\ce{H2C2O4 + KMnO4 + H2SO4 -> CO2 + MnSO4 + K2SO4 + H2O}$$
My book's solution:
Oxidation half-reaction:
$$\ce{C2O4^2- -> ...
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Why did my book write S2- if hydrogen sulfide isn't ionic?
Problem:
Balance the following reaction using the ion-electron method:
$$\ce{KMnO4 + H2SO4 + H2S -> MnSO4 + S + K2SO4 +H2O}$$
My book's solution:
Oxidation half-reaction:
$$\ce{S^{2-}->S + 2e^{-}...
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Is potassium permanganate an oxidizing agent or is the permanganate ion the oxidizing agent?
I have seen both potassium permanganate and the permanganate ion being called the oxidizing agent. Isn't it more appropriate, however, to call the permanganate ion the oxidizing agent only as the ...
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Is haloform reaction considered to be disproportionation? [duplicate]
A question in an exam listed a number of compounds and the task was to find the number of compounds which will undergo disproportionation in conc. $\ce{NaOH}$. One of the compounds was $\ce{CCl3CHO}$, ...
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Why does copper(II) sulfate solution turn black on addition of excess sodium borohydride?
In my laboratory experiment, I was supposed to reduce copper(II) sulfate to copper by means of $\ce{NaBH4}$, an indication of which was supposed to be a colour change from blue (copper(II) sulfate) to ...
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Gold cyanidation process
My chemistry book says the following:
In the metallurgy of silver and gold , the respective metal is leached with a dilute solution of $\ce{NaCN}$ in presence of $\ce{O2}$ as a result of which the ...
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Does the length of a salt bridge effect the voltage of a voltaic cell?
I am doing a Chemistry Lab in which it is completely student run. In this experiment, I basically set out the same exact voltaic cell, and used varying lengths of salt bridges as my independent ...
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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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Does hypochlorous acid oxidize hydrogen peroxide?
The following reaction is from https://ncert.nic.in/textbook/pdf/kech202.pdf, p. 11:
$$\ce{H2O2 + HOCl -> H3O+ + Cl- + O2}$$
I have to find if $\ce{H2O2}$ is acting like a reducing agent or an ...
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Can metal displacement reactions happen with insoluable salts?
I know how normal metal displacement reactions work. If one metal is more reactive than the other, they will displace.
For example, normally for this reaction:
$$\ce{Fe_{(s)} + 2AgCl_{(aq)} -> Fe^{+...
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Does hot potassium permanganate break benzene rings?
Benzene rings are broken during ozonolysis, and alkenes treated with hot $\ce{KMnO4}$ undergo oxidative ozonolysis.
So does that mean that the double bonds of benzene also are broken by hot $\ce{...
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Why doesn't XeF6 displace oxygen from water?
Consider the following reactions (unbalanced):
$$
\begin{align}
\ce{XeF2 + H2O &→ Xe + HF + O2} \tag{a} \\
\ce{XeF4 + H2O &→ XeO3 + Xe + O2 + HF} \tag{b} \\
\ce{XeF6 + H2O &→ XeO3 + HF} \...
user121185
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Excess of OH- ions in electrolysis of sodium chloride solution
In the electrolysis of dilute or concentrated sodium chloride solution, at the cathode as hydrogen ions discharge and cause an excess of hydroxide ions, why doesn't the negativity of the cathode repel ...
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What would happen to the cell potential if two half cells of a galvanic cell were at different temperatures?
I'm doing an experiment where I'm investigating the effect of temperature of the galvanic cell on the cell potential. But during the experiment, I noticed that the two half cells were at different ...
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Definition of Oxidation [duplicate]
Most textbooks define "Gain of Oxygen" as oxidation. Why the gain of Fluorine is not included as part of the definitions since Fluorine is more electronegative than Oxygen?
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Reaction between concentrated sulfuric acid and sodium bromide
What are the products of the reaction between sodium bromide and concentrated sulfuric acid?
I did the question like this:
$$
\begin{align}
\ce{2Br- &-> Br2 + 2e-} \tag{R1.1} \\
\ce{SO4^2- 4H+ ...
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Sodium dithionite reduction of nitro group to amine
I've recently come across the synthesis of 3-aminopthalhydrazine from 3-nitropthalhydrazine where the reducing agent used was sodium dithionite ($\ce{Na2S2O4}$). I wanted to know what the mechanism of ...
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Will Lithium displace a sodium salt?
This question is based on a discrepancy I have observed in my limited knowledge about the reactivity and electrochemical series.
In the reactivity series it is mentioned that Na>Li in reactivity ...
user121185
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How to promote oxidation of copper(I) chloride to copper(II) chloride with oxygen in solution?
I recently discovered that copper(I) chloride in hydrochloric acid can react at about 80 °C with bubbled-in oxygen gas and oxidize into copper(II) chloride. I found almost no documentation on the web, ...
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Balancing a chemical reaction with oxidation numbers
We have been teached how to balance chemical reactions with oxidation numbers in school, but somehow I can't understand it.
This is the equation to balance
$$\ce{Cu(s) + NO3−(aq) + H+(aq) -> Cu^2+(...
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In the complete combustion of methane, is it methane or carbon that is oxidised?
I realise this is a rather pedantic question, but I'm wondering which application of terminology is more correct here.
I know that, in the complete combustion of methane, methane is the reducing agent....
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Voltaic cell equilibrium confusion
In a voltaic cell, taking one with $\ce{Zn}$ and $\ce{Cu }$ electrodes for an example, an EMF is formed because the equilibria at the $\ce{Zn}$ electrode is shifted more towards the $\ce{Zn^2+ + 2e-}$ ...
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How is MnS + 2HCl -> MnCl2 + H2S a redox reaction, in terms of electron transfer?
$$\ce{MnS + 2HCl -> MnCl2 + H2S}$$
If oxidation and reduction is taken to be the loss of hydrogen and the gain of hydrogen respectively, then I can see how the aforementioned reaction is redox — $\...
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