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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35 views

Predicting possibility of oxidation by observing Standard oxidation potential

How can we judge possibility of oxidation by seeing the oxidation potential? OR What is the relation between Standard oxidation potential (S.O.P.) and quality of oxidation ? By quality I mean the ...
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what happens if iron clamp is attached to a copper pipe to a wall?

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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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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25 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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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
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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 ...
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1answer
149 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 ...
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1answer
486 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: ...
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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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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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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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2answers
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Hydrogen Peroxide & Vinegar Film reversal, can someone help me understand this reaction?

I'm interested in DIY photo development and I came across a reversal process that uses chemicals easily available at the grocery store. The purpose of a reversal process is to take a partially ...
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1answer
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What is the n-factor of ferric sulfide when it reacts with oxygen to give ferrous sulfate and sulfur dioxide?

What is the n-factor of $\ce{Fe2S3}$ in this reaction? $$\ce{Fe2S3 + O2 -> FeSO4 + SO2}$$ I broke this reaction down into two parts $$\ce{Fe2S3 -> FeSO4}$$ $$\ce{Fe2S3 -> 3 SO2}$$ And in the ...
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How is this reaction not a decomposition reaction? And are all disproportionation reactions decomposition reactions?

When I asked my teacher whether all disproportionation reactions are decomposition reactions, he stated the following reaction: $$ \ce{4 KClO3 -> 3 KClO4 + KCl} $$ and said that this isn't a ...
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Oxidising power of oxides of 15th group elements [closed]

In case of oxides of 15th group elements in form of $\ce{M2O3}$ ($\ce{M}$ is the 15th group element), does oxidising power of oxides increase or decrease down the group? I tried to check by comparing ...
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2answers
111 views

Are all hydrolysis reactions non-redox reactions? [closed]

Are all hydrolysis reactions always non redox reactions? For example: $$\ce{N2O3 + 2H2O -> 2HNO2}$$ The main reason I say that this statement is correct is because oxygen and hydrogen generally ...
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Mechanism for reaction between carboxylic acid and manganese(II) oxide [closed]

I am reading about redox reactions of carboxylic acids with $\ce{MnO}$ but I couldn't find any mechanism online,so can any one provide the mechanism.
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1answer
104 views

How to balance the reaction equation between copper (I) sulfide and nitric acid?

What is the sum of stoichiometric coefficients of redox reaction: $\ce{Cu2S + HNO3 -> S + NO2 + Cu(NO3)2 + H2O}$? This exercise is from a multiple choice exam. I have balanced the equation: $$\ce{...
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1answer
42 views

Effect of side reactions on galvanic cell using iron rod as anode and sodium chloride as salt bridge

We just made a galvanic cell on a chemistry lesson using iron, iron sulfate , copper and copper sulfate. We used a sponge soaked in $\ce{NaCl}$ solution as the salt bridge. The issue is that we ...
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1answer
174 views

Procedure for measuring EC

Most of the procedures on the internet are of a university research lab level. Is there a simpler method I could use to determine the concentration of EGCG
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1answer
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What product is created in a zinc - nitrate reaction? [closed]

Question: Place 2 mL of Nitric acid in a test tube and add a small piece of Zinc turning I thought that the overall net ionic equation would be: $$\ce{Zn + 2H+ -> Zn^2+ + H2}$$ Is this correct? ...
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1answer
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Oxidizing properties of sulfuric acid: can it oxidize hydrochloric acid to chlorine?

Can $\ce{H2SO4}$ oxidize $\ce{HCl}$ to $\ce{Cl2}$? I know that $\ce{KMnO4}$ can do it, but my question is considering $\ce{H2SO4}$. In sulfuric acid, sulphur is in +6 oxidation state and in $\ce{KMnO4}...
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3answers
106 views

How does copper oxidise alcohols?

Consider for example ethanol being heated in the presence of copper at 300 °C. How does it give ethanal as a product? Copper being in its elemental state (oxidation state 0). Since negative oxidation ...
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Temperature at which the reaction Oxalic acid + KMnO4 becomes autocatalytic

As described many times, the reaction between oxalic acid and potassium permanganate can be autocatalytic due to the production of Manganese ions. I've read that this only occurs at higher ...
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2answers
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Why would electrode be positively charged in electrolysis?

From my understanding, a battery provides a driving force to pull electrons from the anode, thus the anode becomes positively charged. Suppose the anode is copper, the process should be as follows: $\...
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103 views

Will potassium permanganate react with ferric chloride?

I came across a question : Which of the following compound does not decolourise an acidified solution of $\ce{KMnO4}$? Answer was: After doing a bit of research I found that $\ce{KMnO4}$ oxidises $\...
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43 views

Comproportionation reactions

Is the following reaction a comproportionation reaction? $\ce{NH4NO3 -> N2O + H2O}$ The wikipedia definition says: Comproportionation or synproportionation is a chemical reaction where two ...
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What does the horizontal axis on cyclic voltammograms mean?

In cyclic voltammograms (like the one in the attached image) what exactly is the horizontal axis' voltage refering to? Is it the measured voltage between the reference electrode and working electrode? ...
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1answer
111 views

Does lead(II) chloride dissociate into Pb²⁺ and Cl⁻ ions in HCl?

While solving JEE Advanced 2020 (Paper 2) questions, I came across this particular question: Q.10 Choose the correct statement(s) among the following. (A) $\ce{SnCl2 · 2 H2O}$ is a reducing agent. (B)...
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171 views

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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1answer
43 views

Iron-II to iron-III change in complex formation

We have an iron dust sample, which is treated with hydrogen chloride in aqueous solution. The solution enters in a reaction with a sodium hydroxide powder, from which we obtain a precipitate. Could we ...
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27 views

Is it the solution energy or the reduction potentials (or both) that drives a galvanic cell?

I have received conflicting explanations for why the redox reaction in a galvanic cell occurs. Explanation 1: Some say that it occurs because the anodic metal dissolves more easily than the cathodic ...
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2answers
325 views

Balancing reaction between copper and nitric acid given the ratio of formed nitrogen oxides

Problem $\ce{Cu}$ reacts with $\ce{HNO3}$ according to the equation $$\ce{Cu + HNO3 -> Cu(NO3)2 + NO + NO2 + H2O}$$ If $\ce{NO}$ and $\ce{NO2}$ are formed in 2:3 ratio, what is coefficient of $\ce{...
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1answer
115 views

Balancing redox reaction of zinc and hot diluted nitric acid

I need to balance the following reaction: $$\ce{Zn + HNO3 -> Zn(NO3)2 + NH4NO3 + H2O}$$ I assigned all oxidation numbers: $$\ce{\overset{0}{Zn} + \overset{+1}{H}\overset{+5}{N}\overset{-2}{O_3}\...
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1answer
60 views

How to convert cell diagram to a chemical equation?

How would one convert on the right side of the cell diagram: $$\ce{Zn(s) | Zn^2+(aq) || MnO4-(aq), Mn^2+(aq), H+(aq) | Pt(s)}$$ $$ \begin{align} \ce{Zn(s) &-> Zn^2+(aq)} \tag{ox}\\ \ce{MnO4-(aq)...
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1answer
56 views

Why did we introduce the concept of oxidation number in chemistry? [duplicate]

Isn't oxidation number a weird concept? It assumes complete transfer of an electron from a more EN to a less EN atom per covalent bond formed. This assumption isn't even true. We know that partial $δ^+...
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At what concentration would copper sulphate crystallise at 25 degrees Celsius?

I am doing an experiment on how increasing concentration of copper sulphate affects the voltage in a galvanic cell. The voltage increased as temperature did until 2M where it started to decrease. I ...
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1answer
30 views

Reasoning for redox reactions to be classified as such

Could anyone help me out solving this question regarding redox reactions? I am fairly new to this topic. Which of the following is a redox reaction? (1) $\ce{NaCl + KNO3 -> NaNO3 + KCl}$ (2) $\ce{...
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1answer
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Explanation of rusting of iron through metallic bonding [closed]

In the diagram , colour representations : [O - oxygen atoms , red dots - electron ] I will explain rusting of iron due to metallic bonding as I have understood from online. Please correct me if I’m ...
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1answer
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Adjusting redox reactions

$$\ce{KCl + KMnO4 + H2SO4 -> K2SO4 + MnSO4 + H2O + Cl2}$$ Attempt. I want to adjust this redox reaction, I've figured out that Chlorine and Manganese are the 2 elements that change thier oxidation ...
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1answer
95 views

Does 50% hydrogen peroxide dissolve gold?

We have seen that the silver electrodes on a piezo element are being seemingly dissolved by exposure to our mixture of $50\,\%$ hydrogen peroxide. I was wondering if we were to switch to gold ...
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1answer
69 views

Copper plating with electrolyte not working (Cu(OH)2 vs CuSO4)

I've been experimenting using electroplating, and I recently made a solution by placing two copper pieces connected to a voltage source, in water. I suspect that this created copper(II) hydroxide, as ...
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2answers
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How do I write a balanced redox reaction for the oxidation of chalcocite [(Cu2S) (s)] by O2 (g) to form Cu2+ (aq) and SO42- (aq) [closed]

I'm not exactly sure how to get the oxidation and reduction half reactions. Any help will be much appreciated!
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22 views

Can you calculate the oxidation potential of an ion?

Is there any way to calculate the oxidation potential of [Fe(OH)(H2O)5]+? I am unsure if it can be done since I have only seen oxidation potentials provided for specific reactions of single elements, ...
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1answer
66 views

How do acids prevent ferrous sulfate from getting oxidised?

If $\ce{FeSO4.7H2O}$ is dissolved in an acidic environment, for example in 0.05 M aqueous solutions of methanoic or ethanoic acid, would that prevent it from getting oxidized if an oxidizing agent ...
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1answer
78 views

Balancing redox reactions

This has gotten me confused since long. Not all equations have clean half- reactions, some cations are in more than one compound while some anions are in some other compounds. Some reactions don't ...
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1answer
102 views

Question regarding the colour of Benzoic acid and Benzyl alchohol

This question is primarily based on the Cannizzaro reaction, where a base induces a disproportionation reaction of non-enolizable aldehydes (benzaldehyde, formaldehyde, etc) to form an alcohol and a ...
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2answers
40 views

Why transition metal chloride complex have lower reduction potential than metal aqua ions?

Why transition metal chloride complex have lower reduction potential than metal aqua ions? For example: $$ \begin{align} \ce{Au^3+(aq) + 3 e- &-> Au(s)} &\quad E^\circ &= \pu{+1.52 V}\...
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3answers
193 views

How does the addition of NaCl to the cathode side effect the potential of a voltaic cell: Zn(s) | Zn2+(aq) 0.1M || Cu2+(aq) 0.1M | Cu(s)

By addition of $\ce{NaCl}$ to the $\ce{Zn}$ side of the cell, I observed precipitation of $\ce{ZnCl2}$. I measured the voltage to $\pu{1.05 V}$ before adding $\ce{NaCl}$ to the cathode side, I then ...
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1answer
108 views

Determining iron content by titration

The redox reaction is $$\ce{KMnO4-(aq) + 8 H+(aq) + 5 e- -> Mn^2+(aq) + 4 H2O(l)}.$$ Where does $\ce{H+}$ come from in this reaction? What happened to $\ce{K+}$ in potassium permanganate?

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