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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Enthalpy of electrochemical redox half reactions with O2, H2 and H2O
I am working with numerical analysis of solid oxide fuel cells. In such systems we have an oxidation reaction taking place in the anode, and a reduction reaction taking place in the cathode.
Oxidation:...
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oxidising cysteine to cystine in hair shaft
Is there any non-toxic chemical/oxidising agent/catalyst that can oxidise broken disulphide bonds (UV damaged/ bleached hair) i.e. cysteine to cystine in hair shaft (without reacting with other amino ...
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Redox mass balancing trouble
I'm a university student. I've been given the following redox to study and balance using ionic-electronic method:
$$CuS_{(aq)} + HNO_{3(aq)} \longrightarrow Cu(NO_3)_{2(aq)} + H_2O_{(l)} + SO_{2(g)} + ...
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how does increasing the concentration of a different cation (like Mg) electrolyte effect the rate of copper electrolysis?
I researched alot but I haven't found a clear-cut answer to my question. I believe that the increased overall conductivity would increase the rate of electrolysis, but I feel like the Mg could be ...
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Electrons in Nernst equation depend on how it is balanced
Using the following equation: $K = \mathrm{e}^{zFE/RT}=10^{zE/0.059}$ (standard conditions) and the following disproportionation reaction:
\begin{align}
\ce{BrO- + 2e- + H2O &-> Br- + 2OH-}\\
...
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Oxidation of Toluene with Permanganate in Acidic and Basic Environment
So, in my current undergrad organic chemistry course, we were introduced to oxidation using permanganate. I know that alkenes can be oxidised to carbonyl compounds using hot, acidic KMnO4, but in our ...
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Decomposition Redox Rxn Vs. Intramolecular Redox Rxn [closed]
I'm trying to understand what is the difference between decomposition redox reaction and intramolecular redox reaction? Are they synonymous? Is there a reaction which belongs to one but not the other ...
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How to balance this redox reaction: Fe(NO₃)₂ --> Fe₂O₃ + NO₂↑ + O₂↑ (electronic balance)? [closed]
How can I balance such kind of chemical equation:
$$\ce{Fe(NO3)2 -> Fe2O3 + NO2↑ + O2↑}$$
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Correct interpretation of Impedance: IR-Drop and Nyquist plots
Good day guys,
I have been lately studying impedance and IR drop in electrochemical systems.
From my readings I have come across different interpretations.
According to my books, from the Nyquist plot:...
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Irreversible uncharged acid/base indicator
I am conducting a process in an electrochemical cell where at the cathode or anode surface the pH might be acidic or basic. To figure out if either one is correct I would like to find a reaction that ...
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Nitrogen fixation
As of today (2024.06.20), Wikipedia tells:
Nitrogen fixation is a chemical process by which molecular dinitrogen ($\ce{N2}$) is converted into ammonia ($\ce{NH3}$)
Obviously, this is only half of ...
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How to quantify the concentration of sodium nitrate leftover from eutrophication through titration?
In my experiment, I am trying to quantify the nitrate absorption by duckweed. I need a titration method to measure the left over nitrate levels in the solution. However, this is to be done in a school ...
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What is reduced in the reaction of magnesium with oxygen? [closed]
What is reduced in the reaction $$
2\mathrm{Mg} + \mathrm{O}_2 \rightarrow 2\mathrm{MgO} $$
An oxygen molecule or an oxygen atom ?
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Does a decomposition redox reaction with a single reactant and non-elemental products exist? [closed]
Does a decomposition redox reaction exist with a single reactant and non-elemental products and that this decomposition reaction cannot be decomposed in any condition to yield elemental products.
For ...
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It is possible to synthesize 3,3-diethylpentane ("tetraethylmethane") from carbon tetrachloride?
Compounds like tetraethyl silane or tetraethyltin can be made from their tetrachlorides using ethylating Grignards, but what about substituting carbon, would it work or steric hindrance would prevent ...
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Etching stainless steel
I need to etch some stainless steel for a project. I found some instructions that only require household chemicals (it's kind of hard to acquire chemicals here). It required 30% HCl and 3% H2O2. I ...
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Criterion for a good explosive
For a mixture to be good explosive, it's components should react violently. In other words it should release more energy in less time. Thus enthalpy change of the reaction should be very high and rate ...
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How can reduction and oxidation occur separately in batteries if they're meant to be one reaction?
According to this page along with many others, oxidation and reduction must occur simultaneously. However, in a battery, it seems like they actually occur separately. Oxidation must first occur to ...
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Why isn't NO considered combustible?
According to this (and a bunch of other sources), NO (nitric oxide) is not combustible. But that same source says NO rapidly reacts with O2 to produce NO2, which I thought was the definition of ...
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Standardizing alkaline ferricyanide solution [closed]
The ferricyanide method of determining reducing sugars is simple but I need clarity on time of addition of potassium iodide solution. I am unable to observe change in color from yellow to blue. I even ...
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Indirect Titration of Sodium Bisulfite with Potassium Iodate
I'm trying to develop a procedure to determine the concentration (in g/ml) of a solution of sodium bisulfite (NaHSO3). I have already determined the solution concentration using a direct titration ...
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Determining an unknown E° from two similar half ox/redox reactions
Use the oxidation half-cell and reduction half-cell, $\ce{Cr^3+/Cr^2+} = \pu{0.424 V}$ and $\ce{Cr^3+/Cr2O7^2-} = \pu{1.32 V}$, to determine the $E^\circ$ for $\ce{Cr2O7^2-/Cr^2+}$:
a. $\pu{-1.75 V}$
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Quenching reagents for specific reaction
A reaction general procedure is given as follows:
A mixture of 2-fluoro-5-iodo pyridine $(\pu{1.0 mmol})$, methyl
acetoacetate $(\pu{3.0 mmol})$, $\ce{CuI}$ $(\pu{10 mol\%})$, $\ce{K3PO4}$ $(\pu{3.0 ...
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Change in Gibbs energy for lithium redox reaction
I was reading an electrochemistry book by Thomas F. Fuller, in this book the thermodynamic values for the lithium redox reaction at standard conditions are the following:
Reaction
$\Delta G^o$ [kJ/...
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How to predict whether a redox or an acid-base reaction will occur? [duplicate]
I've been thinking a lot about this question, but even after intense research, I didn't find any satisfying answer, even here. So here's my question, illustrated with an example:
We have a negatively ...
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Does catechol give Tollens’ test?
Do hydroquinones like catechol or p-hydroxyphenol give Tollens’ test?
I know that β-diketones can reduce Tollens’ reagent to give a “silver mirror”, so I would guess that due to tautomerization ...
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Equations for the Winkler method
I learned in my IB chemistry class that the chemical equations for the Winkler method are as follows.
Step 1 2Mn2+(aq) + 4OH-(aq) + O2(aq) → 2MnO2(s) + 2H2O(l)
Step 2 MnO2(s) + 2I-(aq) + 4H+(aq) → Mn2+...
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What reaction takes place when ammonia and sulfur dioxide are introduced into barium chloride solution?
What reaction takes place when gaseous $\ce{NH3}$ and $\ce{SO2}$ are introduced into $\ce{BaCl2}$ solution and an insoluble white solid is produced?
I think that the white solid could be $\ce{BaSO4}$ ...
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Energy released by aluminum reactions
I heard that aluminum reacts violently when exposed to hydrochloric acid. I was wondering how much energy is released by this reaction. Preferably in MJ/kg or MJ/l. Assuming the reaction needs 2 moles ...
user145192
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Hydrogen oxidation number
I am aware that since 2005, IUPAC guidelines established that hydrogen is more electronegative than all elements from group V in the periodic table (you can check official documentation). Thus, $\ce{...
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Why are we permitted to add things to balance redox equations?
Consider balancing redox half equations.
As a general rule, we can add electrons, water, hydrogen ions or hydroxide ions to balance the redox half equation. However, it is not entirely clear why we ...
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Inconsistency in balancing of the equation for lead sulfide oxidation by ozone [duplicate]
The following question was asked in JEE Examination :
$\pu{1 mol}$ of $\ce{PbS}$ is oxidized by $X\ \pu{mol}$ of $\ce{O3}$ to get $Y\ \pu{mol}$ of $\ce{O2}$ :
The answer to which is given as 8.
If I ...
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Does the electric field of a battery exist before a wire is connected outside?
Imagine a galavanic cell.
What I am wondering is, what causes the inital oxidation of the less nobel metal to occur initally. Is the electric field there before you connect a wire, which would allow ...
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Redox half-reactions involving gold at three distinct oxidation states
I am preparing for my exam, and for some reason really struggle with half-reactions in the context of Galvanic cells. I do manage to solve the more straight forward questions, but really struggle with ...
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How to deduct the concentration of chloride in a silver/silver chloride electrode, given the cell notation
I have this cell notation:
$$ \ce{Zn|ZnCl_2(0.05M)||AgCl(s)|Ag} \tag{1} $$
What is the physical shape of this cell? I know $\ce{AgCl}$ has very low solubility, and the problem has no concentration on ...
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How to explain oxidizing power from Molecular Orbital Theory
I am trying to explain the oxidizing property of $\ce{Fe^3+}$ in $\ce{H2O}$ and $\ce{CN^-}$ which is $\ce{[Fe(H2O)6]^3+}$ and $\ce{[Fe(CN)6]^3-}$.
The electrochemical reactions along with their ...
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Aqueous electrons in electrochemical cells [closed]
In the context of a zinc-copper electrochemical cell, zinc atoms at the anode are oxidized, releasing electrons and forming zinc ions that dissolve into the solution ($\ce{Zn(s) -> Zn^{2+}(aq) + 2e-...
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Non-catalysed exhaust gas
I'm writing up an academic paper (medical) on in-car exhaust levels and their effect on health. So as to ensure detection of leak-points that are located further along than the catalytic converter, in ...
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Copper reaction with nitric acid
According to this paper, the green colour from the reaction of copper and nitric acid could be explained:
The color is greenish, probably as a result of a combination of the
pale-blue color of the ...
user139387
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Neglected partial pressures dependence of water splitting
I am studying electrochemical water splitting and I have a huge doubt. The standard redox potential for the total reaction is 1.23 V, but this is in standard conditions, where the hydrogen and oxygen ...
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Oxidation of compounds vs elements
I was under the impression that when talking about oxidation/reduction, we are referring to specific elements, and the changes in their oxidation numbers.
However, I saw the following reaction ...
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Is it possible to make thermite that detonates? [closed]
Why does thermite burn pretty slowly? Can it burn much faster if the components were ground to much smaller grain sizes? Can it be made to actually detonate--that is, the entire pile turning into ...
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Oxidation of Isopropanol by Permanganate in Basic Solution
so I've been designing an experiment where I will explore the effect of isopropanol concentration on the colour change of a solution containing permanganate, isopropanol, and NaOH.
I know that the ...
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How can I refine my method of determining iron content in spinach?
I have begun a chemistry experiment that attempts to determine how iron content in spinach is affected by the length of time it is cooked. Through research, I learned that iron content is often ...
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How does electric current flow in daniell cell?
The actual question in my mind is that ……..at anode zinc oxidises to form $\ce{Zn^{2+}}$ and $2$ electrons, but it should be the same case at cathode because copper should also oxidise to form $\ce{Cu^...
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Help in balancing redox reaction
I've started balancing redox reactions, and one particular reaction has tripped me up.
$$\ce{PbS + O3 -> PbSO4 + O2}$$
$\Delta ON$ for $S =8$
$\Delta ON$ for $O =-2$
Here, $O_2$ acts as a spectator ...
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Disproportionation reactions
Are there any examples of a disproportionation reaction being harnessed to do useful electrical work? It is of course possible in a comproportionation reactions, such as a lead-acid cell.
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How do electrons travel through a fuel cell or flow battery with multiple cells?
I understand that if you have a fuel cell or flow battery with a single cell that electrons will go from the electrode and through an external circuit across the load which the fuel cell / flow ...
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Redox Reaction Half Equations
$$\ce{PbS(s) + 4 H2O2(aq) -> PbSO4(s) + 4 H2O(l)}$$
I been trying to find the half equations for a while now. How would you find the balanced half equations for this redox reaction? Do you just add ...
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Using biochemical standard state versus chemical standard state
Can I use the table below to calculate the standard cell potential, $E^{\circ}$, of ethanol oxidation to acetaldehyde (EtOH + 1/2O2 $\rightarrow$ Acetaldehyde + H2O)? Does it matter that the half-...
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