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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32
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1answer
1k views

Flammability (NFPA) - how is it defined?

I was reading up on a wonderful little chemical compound known as chlorine trifluoride ($\ce{ClF3}$). For a primer, check out Dr. Derek Lowe's blog post here: Sand Won't Save You This Time. The title ...
2
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2answers
79k views

What is the balanced equation for the reaction of potassium permanganate, iron sulfate, and sulfuric acid? [duplicate]

I'm trying to balance the following redox equation. I think this is happening in acidic solution, the textbook doesn't specify anything more. Can you please help me understand if I got the half ...
10
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1answer
10k views

How to balance more complex redox reactions?

I'm in an advanced level chemistry course, and so far we've been introduced to balancing redox reactions. The basic ones like $$\ce{MnO4- + Cl- -> Mn^2+ + Cl2}\tag1$$ are pretty easy for me, but ...
0
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1answer
2k views

Bubble formation when aluminium reacts with copper(II) sulfate solution

I recently did an experiment putting pieces of $\ce{Al}$ and $\ce{Fe}$ into copper(II) sulfate solution and I noticed when the piece of aluminium was reacting, tiny bubbles were coming out whereas ...
17
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5answers
10k views

Iron chemistry: acetates for ebonizing wood

I have recently been “brewing” what is commonly called “iron acetate” for ebonizing wood, and I'd like to understand the chemistry of the iron/acetic acid reaction, which should be fairly simple, but ...
3
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2answers
531 views

Confusion about the oxidation state of copper in copper cyanide redissolved with excess cyanide

$\ce{CuSO4}$ when reacts with $\ce{KCN}$ forms $\ce{CuCN}$ while it is insoluble in $\ce{H2O}$. It is soluble in excess of $\ce{KCN}$ due to the formation of the following complex: a) $\ce{K2[Cu(...
8
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1answer
10k views

Why does sodium react with water?

The reaction of sodium with water is quite infamous. $\ce{2Na + 2H_2O \rightarrow 2NaOH + H_2}$ But exactly why does $\ce{Na}$ displace $\ce H$ in $\ce{H_2O}$?
7
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1answer
14k views

How does aqua regia dissolve gold?

I recently learned that aqua regia can dissolve less reactive or noble metals like gold. Aqua regia is a mixture of $\ce{HCl}$ and $\ce{HNO3}$, but separately, neither of these acids dissolve gold. ...
2
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1answer
1k views

What is the complete reaction for Cyanide ions reacting with Thiosulfate?

I was recently studying about the properties of Sodium Thiosulfate, where I came across the fact that $\ce{S2O3^2-}$ reacts with $\ce{CN-}$ ions to produce $\ce{SCN-}$ ions. This was quite useful in ...
5
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1answer
5k views

Why do sodium halides react so differently with sulfuric acid?

Why do sodium halides react so differently with sulfuric acid? \begin{align} \ce{NaF + H2SO4 &-> NaHSO4 + HF} \tag{1a}\label{NaF}\\ \ce{NaCl + H2SO4 &-> NaHSO4 + HCl} \tag{...
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2answers
707 views

Writing half-reaction for the oxidation of iron (III) hydroxide

Here is the unbalanced equation. $$\ce{Fe(OH)2_{(s)} + O2_{(g)} -> Fe(OH)3_{(s)}}$$ Therefore, one half-reaction is $$\ce{Fe(OH)2_{(s)} + O2_{(g)} -> Fe(OH)3_{(s)}}$$ and the other half-...
5
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1answer
166 views

Galvanic cells/redox - confused regarding diagram

I'm not sure if I got this wrong because I interpreted the cell incorrectly. When they have an arrow pointing in to the tube for $\ce{O2}$, does this imply that $\ce{O2}$ is a reactant? If so then B ...
44
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3answers
289k views

Why is it important to use a salt bridge in a voltaic cell? Can a wire be used?

I was learning about voltaic cells and came across salt bridges. If the purpose of the salt bridge is only to move electrons from an electrolyte solution to the other, then why can I not use a wire? ...
18
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3answers
81k views

Why does zinc react with sodium hydroxide?

If zinc is less reactive than sodium, then why does it still react with sodium hydroxide?
3
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1answer
970 views

n-factor for ammonium nitrite?

The given reaction is $$\ce{NH4NO2 \rightarrow N2 + 2H2O}$$ The way I did it was $$\ce{NH4+ \rightarrow \frac{1}{2} N2 + 4H+ + 3e-}$$ and $$\ce{NO2- +3e- +4H+ \rightarrow \frac{1}{2} N2 + 2H2O}$$ ...
2
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0answers
35 views

Can catecholamines be quantified by HPLC-MS/MS at high pH?

It seems that most HPLC-MS/MS methods used for quantitation of catecholamines (epinephrine, norepinephrine and dopamine, specifically) operate at low pH (commonly 3.0), and therefore demand the ...
-3
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1answer
451 views

What happens in the reaction of hydrogen peroxide with potassium iodide in acidic environment? [closed]

I would like to know how the products form in the following reaction: $$\ce{H2O2(aq) + 2KI(aq) + H2SO4(aq) -> I2(aq) + K2SO4(aq) + 2H2O(l)?}$$
0
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2answers
2k views

Why can't sodium salts be produced through a reaction between a metal and an acid?

I am writing a lab report for the preparation of sodium sulfate crystals. This question came up: Why can the reaction between a metal and an acid not be used to make sodium salts? In this case, could ...
-3
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2answers
196 views

What is reduced and oxidized when potassium bromate reacts to oxygen and postassium bromide?

I'm trying to help lead my daughter to a solution and my high school chemistry is almost 30 years ago. For the following reaction, indicate the species being oxidezed and reduced and show the ...
4
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1answer
182 views

Balancing using oxidation number method

Balance the following equation using oxidation number method: $\ce{PbS + H2O2 -> PbSO4 + H2O}$ Attempt: I have written down the oxidation states of all atoms and we can observe reduction of ...
5
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1answer
780 views

Finding the Oxidation number

I have got the homework to balance the following redox reaction. $\ce{Cr(OH)3- + HO2- -> Cr2O7^{-2} + OH- }$(Basic medium) To balance this reaction first thing we need to do is to find the ...
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0answers
217 views

Why add NaBH4 slowly to 4-t-butylcyclohexanone in ether solution? [Lab Procedure]

$\ce{NaBH4}$ is to be added slowly to 4-t-butylcyclcohexanone in ether solution according to laboratory procedures, but I am curious as to why that is? 4-t-butylcyclohexanone undergoes reduction with $...
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1answer
730 views

Which alcohols change CrO3/H2SO4 from orange to green? [closed]

Which of the following sets of compounds cannot turn a clear orange solution of $\ce{CrO3/H2SO4}$ to a greenish opaque solution? (More than one answer is correct) A) Ethanol B) 2-Propanol C) t-...
2
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1answer
68 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 ...
5
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1answer
4k views

How does a Lewis acid differ from an oxidizing agent; Lewis bases from reducing agents?

A Lewis acid is defined as an electron acceptor. An oxidizing agent is also defined as an electron acceptor (in the electronic theory of oxidation). So then what is the basic difference between an ...
5
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1answer
2k views

Yellowish tinge during titration of oxalic acid with potassium permanganate

One of the our chemistry practicals involve finding the molarity of an oxalic acid solution by titrating it with standard $\ce{KMnO4}$ solution. The oxalic acid solution is heated and little sulfuric ...
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1answer
75 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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1answer
2k views

Can I perform electroplating with sodium carbonate and copper?

I want to avoid anything poisonous during electroplating. I can't avoid copper oxide though. I have dissolved $\ce{Na2CO3}$ in water and I'm trying to electroplate aluminium with copper: As you can ...
6
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1answer
31k views

How to identify a redox reaction?

Which balanced equation represents a redox reaction? \begin{align} &\mathrm{A.} &\ce{AgNO3 + NaCl &-> AgCl + NaNO3} \\ &\mathrm{B.} &\ce{BaCl2 + K2CO3 &-> BaCO3 + 2KCl} ...
1
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1answer
309 views

What reaction occurs when etching copper to create circuit boards?

The components used for etching copper are acetic acid, hydrogen peroxide and sodium chloride. I think the equation may be similar to this: $$\ce{2H3C2O2H + H2O2 + 2NaCl + Cu -> CuCl2 + 2H3C2O2Na +...
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0answers
32 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
2answers
99 views

What are the other end products in sulfur oxoacid formation?

I got this reaction and I can't figure out the end products $$\ce{SO2 + S + CaO + Na2SO4 -> Na2S2O3 + ~?}$$ I am guessing some calcium sulfur salt should form, but which one?
5
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1answer
512 views

Disproportionation with aqueous NaOH

Which of the following undergoes disproportionation with $\ce{NaOH}$? $\ce{SiO2}$ (silicon dioxide) $\ce{CO2}$ (carbon dioxide) $\ce{SO2}$ (sulfur dioxide) $\ce{SO3}$ (sulfur trioxide) ...
4
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0answers
183 views

Comparing two oxidizing agents using electron configuration

Which oxidizing agent from the pair $\ce{K_2IrCl_6/K_2PtCl_6}$ is stronger? Explain your answer using their electron configurations. We write the electron configurations for $\ce{Ir/Ir^{4+}}$ and $\...
-5
votes
2answers
19k views

How to calculate the equivalent weight or N-Factor of compound(acid, salt, base or etc) using electrolysis concept

Our sir, told us about the concept of equivalent weight using electrolysis and Faraday's Law of electrolysis. We got to know ...
11
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7answers
11k views

Does NaOH react with K to form NaOK or KOH?

I realized that the $\ce{-OH}$ group when it reacts with some metal like $\ce{Na}$ or $\ce{K}$ will replace the $\ce{H}$ element to form $\ce{-OK}$ or $\ce{-ONa}$: \begin{align} \ce{H2O + Na &...
3
votes
1answer
124 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 "...
2
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3answers
35k views

How does the reaction of HCl and KMnO4 proceed?

I don't get how does this reaction of hydrochloric acid and potassium permanganate proceeds: $$\ce{HCl + KMnO4 -> KCl + MnCl2 + Cl2 + H2O}$$ What I know: $\ce{HCl}$ dissociates into $\ce{H+}$ ...
3
votes
1answer
644 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)} -&...
3
votes
1answer
728 views

Oxidation of conjugated dienes into carboxylic acids by potassium permanganate

In the book - MS Chouhan; Advanced Problems In Organic Chemistry; 11th ed, Chapter Alkenes Q32 - the following reaction is given: The given solution says that: Conjugated dienes on oxidation by $\...
10
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2answers
7k views

What does the phrase “reducing atmosphere” mean in quantitative terms?

There is a debate about "how reducing" the atmosphere of the early Earth was, and this question is my attempt to grasp toward an understanding of what that that phrase really means. As a bit of ...
8
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1answer
156 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 ...
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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 ...
1
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1answer
10k views

Potassium permanganate (VII) + glucose + sodium hydroxide =?

I saw this experiment many times but still can't explain why. The experiment is first prepare two solutions. The first one is to dissolve potassium permanganate crystal into distilled water to form ...
1
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7answers
6k views

Solving carbon black

I want to remove a layer of 2 mm thick carbon black on a copper bowl on the outside from hanging over wood and coal fire. I have tried different solvents, but the carbon seems to be very resistive. ...
1
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1answer
117 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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1answer
49 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 ...
0
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2answers
244 views

Lead-Acid Battery: Standard Electrode Potential

I'm making a lead-acid battery for an investigation. Since I only had sulfuric acid and lead electrodes, I decided to firstly run 2 lead electrodes through electrolysis in a sulfuric acid electrolyte. ...
1
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1answer
626 views

How to write half equations based on oxidizing/reducing agents pairs?

In most videos, people use oxidation numbers to find the oxidizing agent and the reducing agent, It's a great way to use, but our teacher never used it before he would give us a reaction and ask us ...
7
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2answers
929 views

Determining the redox half-reactions of single displacement reactions

For the following double displacement half reaction, the half reactions can be determined easily using the oxidation numbers. $$\ce{MnO4- {(aq)} + IO3- {(aq)} -> MnO2 {(s)} + IO4- {(aq)}}$$ We know ...