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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.

2
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1answer
66 views

Not sure why, but I can't modify/balance this equation

I'm working on modeling a few reactions for my research. For example: $$\ce{CO2 + H2S + CH4 <=> CH3SH + H2O}$$ was one I grabbed from the literature. However, this reaction is taking place in ...
-1
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1answer
63 views

Balancing the intermolecular redox reaction

The redox reaction is: $\ce{SO2 + Na2CrO4 + H2SO4 -> Na2SO4 + Cr2(SO4)3 + H2O}$ This is what I tried(tho I got stuck at one point which is indeed the exact reason why I've asked this question): ...
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2answers
112 views

Reduction of hydrogen sulfide by silver

Why can $\ce{H2S}$ be reduced by $\ce{Ag}$ when left in air: $$\ce{2 Ag + H2S -> Ag2S + H2}$$ If silver is a noble metal that should not reduce hydrogen?
1
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0answers
30 views

When can colourimetry be used to determine the rate of reaction?

Can colourimetry be used if a coloured reactant react to give a coloured product? For example, in the reaction of reacting dichromate ions with oxalate ions in acidic environment, where dichormate ...
3
votes
1answer
275 views

Reaction of solid silver sulfide on warming with dilute nitric acid

Solid silver sulfide is warmed with dilute nitric acid. I thought that the nitric acid would engage with silver sulfide in a double displacement reaction, as follows: $\ce{Ag_2S {(s)} + 2H+ {(aq)} -&...
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0answers
43 views

Why do we need iodometry?

In case of iodometry where we need to find the concentration of an oxidant, we react it with $\ce{I^-}$ and check how much $\ce{I_2}$ is produced. Then we use a reducing agent with known volume & ...
1
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0answers
42 views

Why is this redox reaction possible?

I have the redox reaction $\ce{N_2H_4 {(g)} + N_2O_4 {(g)} -> N_2 {(g)} + H_2O {(g)}}$. In $\ce{N_2O_4 {(g)}}$, the oxidation state of nitrogen is $+4$. In $\ce{N_2 {(g)}}$, the oxidation state of ...
8
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1answer
120 views

Does chlorine trifluoride react with candlewax?

I've run across references to chlorine trifluoride quite a lot. It pops up fairly regularly on the Worldbuilding SE, and whatever idea people have with it is usually shot down very quickly - For ...
3
votes
1answer
82 views

Maximum possible hypochlorite concentration from electrolysis?

For reference, "electrochlorination" is just the electrolysis of a simple solution of water and table salt (NaCl) followed by reintroducing the chlorine gas produced. But, the Wikipedia article on "...
0
votes
1answer
102 views

Why is the conjugate of a strong oxidizing agent a weak reducing agent?

I am a grade 12 student. While I was reviewing some electrochemistry, I had the following question. Take this reduction half-reaction: $$\ce{F2 (g) + 2e- <=> 2F- (aq) + $\pu{2.87V}$}$$ I know ...
0
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1answer
44 views

Balancing Redox reaction : with 2 species being oxidized [closed]

I have a redox reaction I found from a chemistry book from the 1970's. Two chemical species are oxidized, the Chromium and Iodine. $\ce{CrI3 + KOH + Cl2 -> K2CrO4 + KIO4 +KCl + H2O}$ Hope someone ...
1
vote
1answer
76 views

Safely lowering bleach pH without chlorine gas?

According to Eurekalert, by lowering the pH of household bleach (e.g., by adding vinegar or citric acid), we can increase $\text{[HOCl]}$ and consequently greatly improve the disinfecting capabilites ...
0
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0answers
48 views

Galvanic Corrosion in a Galvanic cell

I am doing an individual practical at school, which requires us to investigate the reactivity of metals, using galvanic cells. My initial proposal was to investigate the effectivity of different metal ...
1
vote
1answer
229 views

Why is ascorbic acid (vitamin c) readily oxidised in the presence of oxygen?

I know that vitamin c is notoriously unstable in aerobic conditions, but I'm not sure how to explain why it is - is it due to redox potential, acid strength etc?
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2answers
86 views

How to balance redox reactions possessing oxidation number change in multiple elements? [duplicate]

Hello, I am bit confused about balancing these type of redox reactions where multiple elements are involved in oxidation and reduction reactions. If I try to use half reaction ion exchange method and ...
1
vote
0answers
41 views

Methionine/Cysteine under redox control [closed]

Methionine and cysteine are the principal sulfur-containing amino acids, and oxidation of cysteine and methionine residues had been well studied. How come NOT all proteins carry Methionine and/or ...
0
votes
1answer
26 views

Identifying Donation of an Electron Pair

Which one of the following reactions does not involve the donation of an electron pair? A) $\ce{H+ + CH3NH2 -> CH3NH3+}$ B) $\ce{AlCl3 + Cl- -> AlCl4-}$ C) $\ce{CH3Cl + CN- -> CH3CN + Cl-}$...
0
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0answers
70 views

Why does acidic medium accelerate rusting?

When learning about the corrosion of iron, I was teached that the following half-reactions happen: $$ \ce{Fe -> Fe^2+ + 2e- } $$ $$ \ce{2H2O + O2 + 4e- -> 4HO-} $$ First question is: do these ...
0
votes
2answers
97 views

What is the reaction of ammonium nitrate with hypochlorous acid [closed]

What would the product of ammonium nitrate and hypochlorous acid? Would there be any reaction? Would the HOCl get broken down? Trying to determine if the free chlorine content would be diminished upon ...
0
votes
1answer
170 views

What is the purpose of the electrolyte in the half-cell where oxidation is taking place?

In an electrochemical cell that consists of two half-cells, there is an electrolyte and an electrode in each half-cell. Example: $$ \begin{align} \ce{CuSO4(aq) + 2e- &-> Cu(s) + SO4^2-(aq)} \\ ...
0
votes
1answer
50 views

Is the ionic solution of a half-cell part of the electrode in a electrochemical cell? [closed]

A simple electrochemical cell consists of two half-cells, that is: a metal solid submerged in a solution. Additionally, there is salt bridge connecting the half-cells. Ex: $\ce{Cu(s)}$ in $\ce{CuSO4(...
0
votes
1answer
39 views

Why aqueous KI is used when collecting Iodine?

In room temperature solid di-iodine pentoxide($I_2O_5$) reacts with carbon monoside to form carbon dioxide & Iodine. This can be used to measure the amount of carbon monoxide in an air sample. $...
0
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0answers
80 views

The halide ions as reducing agents

So I'm currently an A-level student, and we learnt at some point last year that iodide ions were (at least compared to the halides above it) strong reducing agents - strong enough such that if sodium ...
0
votes
2answers
113 views

Predicting products of chemical equations? [duplicate]

Consider the equation $\ce{2 NaOH (aq) +Cl2 (g) —> NaOCl (aq) + NaCl (aq) + H2O (l)}$. How would one know the products of this reaction? Is there a general way of doing this? I would have no ...
1
vote
1answer
1k views

Balancing the reaction of potassium permanganate and sulfuric acid with hydrogen peroxide [duplicate]

A problem on redox reactions invites the reader to balance the actual reaction from which the redox simplification arose. After some hunting I found the balanced equation and attempted to re-derive ...
0
votes
2answers
40 views

Zinc and copper salt bridge replacement [closed]

If I were to replace $\ce{Zn}$ with $\ce{Al}$ in $\ce{Zn|Zn^2+ || Cu^2+|Cu}$. Would it produce the same results?
2
votes
1answer
112 views

Which is a better oxidising agent: concentrated nitric acid or dilute nitric acid?

I was reading the Wikipedia page on nitric acid and saw the reaction of concentrated $\ce{HNO_3}$ and dilute $\ce{HNO_3}$ with $\ce{Cu}$. It is mentioned that: Copper reacts with dilute nitric ...
0
votes
0answers
26 views

Why is Co³⁺ such a strong oxidising agent? [duplicate]

The reduction potential of Co³⁺ is 1.81 suggesting the very strong oxidising nature of Co³⁺. I wanted to know the reason why is it so?
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votes
1answer
91 views

Examples for oxidation of fluoride and for fluoride as a base

I have no university degree in chemistry and I’m curious about some examples - explained with the applicable rules (or the exception from the existing rules) - for the following statements (from this ...
3
votes
1answer
162 views

How does calcium chloride act as a sequestrant (food science)?

This Wikipedia page lists common sequestrants (with respect to food science). As stated on the page: A sequestrant forms chelate complexes with polyvalent metal ions, especially copper, iron and ...
5
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4answers
481 views

Why is fluorine the best oxidising agent, but also the most basic?

(Please note that all comparisons I have made below are with respect to halide ions only.) According to what I have learnt, the fluoride ion is the most basic ion, because it has the smallest size ...
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0answers
46 views

Can you ignite the thermite reaction in a solution?

As far as I know thermite is a typical redox reaction where $\ce{Al + Fe^{3+} -> Fe + Al^{3+}}$ happens. I guess the activation energy is very high, because you need to split the $\ce{Fe_2O_3}$ ...
0
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0answers
562 views

Reducing nature of hydrogen peroxide in acidic and basic medium

$\ce{Fe^3+}$ is reduced to $\ce{Fe^2+}$ by using $\ce{H2O2}$ in presence of $\ce{NaOH}$ $\ce{Na2O2}$ in water $\ce{H2O2}$ in presence of $\ce{H2SO4}$ $\ce{Na2O2}$ in presence of $\ce{...
0
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0answers
48 views

Is this a redox reaction?

Screenshot of the reaction: To me it seems like nitrogen gets oxidised and oxygen gets reduced, but I think I might be wrong ... What kind of reaction is it then?
3
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1answer
2k views

Explaining the colour change in the potassium permanganate titration of Fe2+ ions

In the redox titration: $$\ce{MnO4- + 8H+ + 5Fe^2+ -> Mn^2+ + 4H2O + 5Fe^3+}$$ the colour change which occurs is purple to colourless, because of the decreased concentration of permanganate ions. ...
-1
votes
1answer
100 views

Phenylalanine reduction to phenylalaninol [closed]

Since phenylalanine is reduced to phenylalaninol in 16-18 hours under reflux with sodium borohydride and sulfuric acid in dry tetrahydrofuran. My question is, to reduce $\pu{100g}$ of phenylalanine, ...
3
votes
1answer
133 views

Reduction half-reaction for the reduction of elemental oxygen

Write the reduction half-reaction for the reduction of elemental oxygen in the presence of water, producing hydroxide ions This does not make sense to me - a half reaction (from what I understand) is ...
-1
votes
1answer
30 views

Why is manganese oxide precipitated during the syn hydroxylation of alkenes with permanganate ion?

During the hydrolysis step, after the formation of the heterocyclic ring, hydrogen permanganate ion is formed but the final product is manganese oxide precipitate. My point - why would permanganate ...
-2
votes
1answer
299 views

Why is oxidation number of Ba not +2 in this case? [closed]

According to redox rules, column 2 elements (alkali earth metals) have an oxidation number of +2, but in this reaction: $\ce{Ba + Cl2 -> BaCl2}$, the oxidation number of $\ce{Ba}$ changes from $0$ ...
8
votes
2answers
556 views

What is the actual mechanism of Fenton reaction?

Fenton reaction was supposedly discovered by Fenton as Tartaric Acid oxidation by hydrogen peroxide in presence of ferrous cation in 1894. Research Paper link. I have worked on this reaction for ...
3
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0answers
38 views

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 desrcibed in ...
3
votes
1answer
71 views

Experimental measurment of thiosulphuric acid decomposition kinetics

Problem I am trying to do a kinetics analysis on the following reaction: $$\ce{Na2S2O3 {(aq)} + 2 HCl {(aq)} -> S {(s)} + 2 NaCl {(aq)} + SO2 {(g)} + H2O {(l)}}$$ Suggested Method However, most ...
0
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0answers
48 views

Is bright orange pulvery backside of mirror mercury II oxide?

I have an old mirror recovered from trash that has a bright-orange pulvery substance on it's backside. The front of the mirror is still reflecting but has darker spots that look like remnants of dried-...
5
votes
1answer
112 views

Why does my sodium acetate look like metalic magma?

I tried to make sodium acetate. Ingredients: Store bought vinegar - 8% acetic acid, water, E150C (caramel) Baking soda - $\ce{NaHCO_3}$ Steps: I first emptied sacks of baking soda to a ...
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0answers
105 views

How does pH affect fluorescence quantum yield?

I have read in a scientific paper that: the light intensity produced by the decomposition 3–aminophthalate in the oxidation of luminol (involving hydrogen peroxide and iron (II) sulfate heptahydrate) ...
2
votes
0answers
62 views

Results of mixing HSbF6 and O2F2

I'm an amateur writer and one of the topics I deal with is what happens when a slightly-mad scientist and engineer is given an opportunity to work with full-on “magic.” So there are situations where ...
1
vote
0answers
104 views

Would stainless steel corrode in this electrolytic cell I designed? [closed]

As far as I know, stainless steel is resistant to corrosion due to an inert oxide layer formed by the other alloy metals. I am learning about redox reactions right now so I am no expert; but since ...
0
votes
0answers
132 views

Is potassium ferricyanide a catalyst for the oxidation of luminol by hydrogen peroxide?

I have searched online on how potassium ferricyanide catalyses the oxidation of luminol by hydrogen peroxide. Apparently it reacts with hydrogen peroxide to produce oxygen. The oxygen then reacts with ...
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votes
3answers
24 views

Where to get electrodes for Microbial fuel cell [closed]

I am currently working on a soil-based MFC. So far I have built myself some carbon electrodes by putting glue on a stainless steel mesh as a current collector and sprinkling activated carbon power ...
3
votes
1answer
68 views

Are my intuitions about how batteries work right? [closed]

Being really fascinated by how electricity actually works, I started studying batteries. I initilally understimated the complexity of this apparently-simple objects, and thorugh studies and researches ...