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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60 views

How to calculate/estimate the contamination rate of ultra pure water (UPW) in the presence of metals?

Metals are known to release ions into ultra pure water. Do any equations or empirical data sets exist for estimating the rate of contamination with different metals? I don't need a specific solution; ...
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0answers
27 views

Equilvalence point in redox Titration of Fe(II) and Fe(III) with Reinhardt-Zimmermann solution

In the lab at university, we need to conduct a simultaneous determination of iron(II) and iron (III) ions using potassium permanganate solution. In the first step, we just fill up our given sample ...
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3answers
2k views

True or false: "A used AA battery contains fewer moles of electrons than a new AA battery."

I recently took a Gen. Chem. 2 exam that contained this question. I answered false, but my professor said the answer is true. My reasoning was that any electrons that leave the anode end up at the ...
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2answers
86 views

The oxidation number of N and Cl in NOClO4 ​

My doubt is not about the solution itself, actually I was able to find the solution myself. We could split NOClO4 as (NO+) + (ClO4-) and then proceed, but here I "knew" this split. Is there ...
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0answers
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Why does nitric acid react with less reactive metals [duplicate]

So we are studying the acid base chapter and I came across these reaction: $$\ce{3Ag + 4HNO3 -> 3AgNO3 + NO + 2H2O}$$ My question is, how can $\ce{Ag}$ react with $\ce{HNO3}$ as it is lower than ...
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2answers
206 views

Why do we need salt in a salt water battery?

I am having problems understanding why we do need salt added to the water to make this shown galvanic cell work. I understand that Zinc wants to dissolve into the electrolyte, resulting in $\ce{Zn^2+}$...
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2answers
379 views

Balancing complex redox reaction in a basic solution [closed]

I'm incredibly lost right now. I understand fully how to balance redox reactions in acidic/basic solutions, but the problem my teacher posted is not letting me use the method taught to us. I've ...
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0answers
88 views

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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1answer
112 views

Why is comproportionation thermodynamically favoured for the synthesis of Mn(acac)3?

I'm currently learning about ligands in school and I'm wondering why does comproportionation happen in the overall equation? There are fewer chemical species on the product side and the entropy of the ...
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2answers
61 views

Where does the free electron from from in Ag/AgCl reaction?

For the Ag/AgCl half reaction, where did the free electron that AgCl captured come from? Did it come from the Ag wire? If so, why would Ag wire give an electron to AgCl, both atoms are Ag and have the ...
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0answers
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Why is addition of electronegative element to a substance considered as oxidation? [duplicate]

I'm confused to why oxidation with its other definitions also defined as addition of electronegative element to a substance, when at the same time in terms of electron transfer oxidation is also the ...
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1answer
49 views

What role does ammonium play in the explosion of ammonium nitrate? [duplicate]

I read that ammonium is the "fuel" and nitrate is the "oxidizer". The nitrate oxidizes because it's a nitro group, but what's the mechanism of the ammonium?
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Redox reaction of cycloheptatriene ligand

The reaction I really don't understand is the second one which produces the cycloheptatriene ring with a positive charge. The only thing I can think of is that the hydrogen is being ejected and ...
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0answers
86 views

Why are holes appearing in this aluminum kitchen foil on my radiator?

I thought I would try to deal with dehumidified air from radiators by filling simple troughs of water placed on the top, which in theory would evaporate water as the radiator heated the air. I crafted ...
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1answer
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What are compounds where oxygen has oxidation state -1/3 called?

I have heard of oxides, peroxides and superoxides where oxygen oxidation number is $-2, -1, -\frac{1}{2}$ respectively. But I came across a molecule with the formula $\ce{KO_3}$, oxygen has $-\frac{1}{...
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1answer
67 views

How do I balance a hydrogen peroxide redox equation? [closed]

I have this equation: $$\ce{H2O2 + MnO4- + H+ -> O2 + Mn^2+ + H2O}.$$ How do I balance it, since O has two different oxidation states on one side?
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2answers
108 views

Effect of H+ concentration on equilibria

Considering the two equilibriums below, when the $[\ce{H+}]$ decreases, my book says that equilibrium \eqref{rxn:2} will shift to the left by a greater extent compared to equilibrium \eqref{rxn:1} ...
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1answer
130 views

Why does mercury(II) nitrate form only when using concentrated nitric acid?

In the reaction between mercury and nitric acid, mercury(II) nitrate only forms when concentrated nitric acid is heated up and added to it, if the acid is dilute, mercury(I) nitrate forms. I ...
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2answers
117 views

Does boron exhibit +1 oxidation state?

My teacher told that boron exhibits only a $+3$ oxidation state, but he also wrote the unbalanced reaction $$\ce{B + C -> B4C}.$$ Carbon has greater electronegativity than boron leaving us with $\...
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1answer
71 views

How can I prevent and remove oxidation on the surface of liquid Galinstan?

The oxide layer formed on galinstan (or its component of pure gallium) when exposed to air increases wetting and dulls the appearance. Is there a clear liquid material in which a blob of liquid ...
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1answer
67 views

How to balance this half-equations [closed]

HNO$_3 \rightarrow $ N$_2$O(g) I'm looking at the solution and it says that the above reaction can be modified as NO$_3^-$(aq) $\rightarrow$ N$_2$O (g) I don't understand why. Can someone please ...
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1answer
57 views

Balancing redox reaction by removing spectator ion SO₄²¯ [closed]

I aimed to balance the equation $$ \ce{Cr2O^{2-}_7 + FeSO4 + H+ -> Cr^{3+} + Fe2(SO4)3} $$ My teacher explained me that since $\ce{SO^{2-}_4}$ is the spectator ion, I must proceed in this equation ...
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1answer
53 views

Fundamentally, what is the difference between redox and acid-base reactions?

For example, consider: $$\ce{NH3 + H2O -> NH4+ + OH-}$$ Here, the $\ce{NH3}$ is acting as a base (By Lewis theory, it is an electron pair donor). Why don't we consider this to be a redox (there is ...
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1answer
85 views

How do I balance redox equations with three reactants?

Could anybody please explain me the concept of balancing redox reactions with three reactants? Either some solving steps or even the solution would be very appreciated. For example, I don't know how ...
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1answer
43 views

Does nascent Oxygen/Hydrogen really exist or just or is it just electron from ionic equation? [duplicate]

Recently I was taught by my teacher that there is no such thing as nascent oxygen neither hydrogen. It just represents Electrons from ionic equations. Then he proceeds to give example of following ...
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1answer
112 views

How to derive formulas for n factor of different types of reactions?

While studying Redox reaction, I came across this term called n-factor which seems to me as a short-cut trick to do the questions quickly. Since I am preparing for a competitive exam so our chemistry ...
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1answer
47 views

Reducing sugars and redox potential

I am wondering if reducing sugars are those that can act as reducing agents, and they act as such with Tollens and Fehling reaction, then what's the redox potential here? And is it a reversible ...
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0answers
46 views

Electrode potential of Br2/HBr half cell

I am wondering if it is possible to find the electrode potential of such a half cell: $$\ce{Br2 (l) + 2 e- <=> 2Br-(g)}$$ The standard electrode potential is for $\ce{Br-(aq)}.$ However, is it ...
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1answer
68 views

Oxygen-releasing material at ≤ 200 °C [closed]

I have to anneal a ceramic in high oxygen pressure, in an autoclave. For this purpose I need a chemical which can release oxygen at temperature less than or at 200 °C. Would appreciate any suggestion. ...
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0answers
31 views

Lithium Air vs Li Fluoride battery capacity [closed]

Lithium air aka lithium oxygen batteries are described as highest theoretical capacity battery possible. In wikipedia, it says lithium air has energy density 5210 Watt hour per kg, including weight of ...
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2answers
111 views

Extraction of copper from chalcopyrite

During the extraction of copper from chalcopyrite ore, the ore ($\ce{Cu2S.Fe2S3}$) is heated to form $\ce{Cu2S}$ and $\ce{FeS}$. Then during smelting it reacts with $\ce{O2}$ to form $\ce{Cu2O}$. Then ...
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Do decomposition potentials change during electrolysis?

I was just wondering if decomposition potentials actually change during electrolysis. For example, if we reversed the Daniell cell reaction so that copper is oxidized, the half cell reactions would be:...
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1answer
84 views

Calculating Gibbs free energy change when the state of ions is unknown

Problem Calculate $\Delta G^\circ$ for the following reaction: $$\ce{Zn(s) + Ag2O(s) + H2O(l) -> Zn^{+2}(aq) + 2Ag(s) + 2OH-(aq)}$$ Given $E^\circ_{\ce{Ag+/Ag}} = \pu{0.80 V}$, $E^\circ_{\ce{Zn^{+...
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2answers
72 views

What gives dilute/conc nitric acid/ conc sulfuric acid their oxidizing property?

I know that dilute sulfuric acid and very dilute nitric acid don't have any oxidizing tendency while dilute/conc $\ce{HNO3}$ and conc $\ce{H2SO4}$ do. Why do these more concentrated acids have this ...
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2answers
107 views

What can be used instead of magnesium to make silicon from sand (in lab)? [closed]

I found this post talking about making silicon from sand. They mixed magnesium with sand and then burn them then it create silicon and magnesium oxide. And my question is what can we use instead of ...
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0answers
51 views

A problem on Intramolecular Cannizzaro's Reaction

My textbook has the following reaction given as a special case of Intramolecular Cannizzaro reaction: As far as I understand, here one Phenyl group migrates (instead of hydride ion) from the carbonyl ...
2
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1answer
73 views

Regarding the oxidation of Manganese(II) ion by Peroxodisulphate ion

The following information is mentioned in my textbook: In the laboratory, a manganese(II) ion salt is oxidized by peroxodisulphate to permanganate. $\ce{2Mn^2+ + 5S_2O_8^2- + 8H2O -> 2MnO4- + ...
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1answer
91 views

What is the mechanism of temporary bleaching of flowers by SO2 ? Can H2S be used?

There are many claims on the web, explaining that the bleach action of Chlorine gas in discoloring of flower proceeds as follow and require moisture for it : $$\ce{ Cl2 + H2O <=> HOCl + HCl <=...
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1answer
90 views

Relation between standard silver-silver chloride electrode potential and solubility product of silver chloride

I learned that $E^\circ_\ce{Cl^-|Ag,AgCl}, E^\circ_\ce{Ag^+|Ag}$ and $K_\mathrm{sp}$ of $\ce{AgCl}$ are related as $$\boxed{E^\circ_\ce{Cl^-|Ag,AgCl} = E^\circ_\ce{Ag^+|Ag} + \frac{RT}{F}\ln K_\mathrm{...
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0answers
83 views

Etard's reaction

My textbook says the following on Etard's reaction: Now, if the alkyl group attached to benzene is an unsymmetrical or branched alkyl group, such as this: What will be the reaction product(s)? Which ...
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2answers
56 views

what happens if iron clamp is attached to a copper pipe to a wall? [closed]

I'm guessing its not a good idea, since iron will then corrode easily (also depending on the location and environment), Although copper do not rust it will increase the rate of it from oxidizing. plus ...
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0answers
43 views

Sodium hydroxide reaction with manganese dioxide [duplicate]

I came across a website that said it is possible for sodium hydroxide to react with manganese dioxide at temperatures near 0 degrees Celsius. The reaction goes: 2MnO2 + 3NaOH ⇄ MnO(OH) + Na3MnO4 + H2O ...
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1answer
29 views

Why is "activity" of gaseous component equal to its partial pressure but that of aqueous component its concentration?

While solving an electrochemistry problem I had to calculate the reaction quotient of this reaction: $$\ce{2Fe(s) + 4H+(aq) + O2(g) -> 2Fe^{2+} (aq) + 2H2O (l)}$$ It turns out to be: $$\ce{Q=\dfrac{...
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3answers
2k views

Can a battery be built where several electrodes share the same electrolyte?

If you have two metals i.e. iron / copper and an electrolyte solution you can make a battery. Typically all of the designs have several of these connected in series to boost the output. But I have ...
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2answers
99 views

Redox reaction between Potassium thiocyanate and iodine

How would you balance the following redox reaction in acidic medium? $$\ce{KSCN + H2O + I2 -> KHSO4 + HI + ICN}$$ In this reaction, it seems the sulfur is being oxidized but iodine is undergoing ...
4
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1answer
160 views

What is the n-factor for reduction of chromate(VI) to chromium?

Here a reaction is given: $$\ce{CrO4^2- -> Cr}$$ I don't know the full reaction, but I made some estimates. One estimate was that on balancing charges we get two electrons on right-hand side. I ...
7
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2answers
563 views

Can hydrogen peroxide reduce ferric ion to ferrous ion?

I have studied that hydrogen peroxide always oxidizes ferrous ion to ferric ion (source of study : NCERT Chemistry Part II, Textbook for Class XI), but a question came in IIT JEE 2015 which states: ...
2
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0answers
72 views

Is hydrogen peroxide a better oxidizing agent than chlorine gas? [closed]

If we compare the standard reduction potentials of $\ce{H_2O_2}$ with that of $\ce{Cl_2}$: $\ce{H_2O_2 + 2H^+ + 2e^- <=> 2H_2O : E^o = 1.78V}$ $\ce{Cl_2 + 2e^- <=> 2Cl^- : E^o = 1.36V}$ (...
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0answers
29 views

Why does the application of external mechanical pressure increase the performance of lithium-ion batteries?

Many electric vehicle batteries - specifically lithium-ion ones considered for this query - can be subjected to external mechanical pressure because it increases battery performance. What components ...
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0answers
32 views

Why do we need salt bridge in a cell during potentiometric measurement as there is no or minimum redox activity at electrodes?

In electrochemical cell, we need salt bridge to maintain electrical neutrility in both halves cells during redox reaction?. But in during potentiometric measurement, no or minimum current is drawn and ...

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