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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7
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2answers
904 views

What are high-energy electrons?

I read that (in cellular respiration) the transported electrons in NADH have a higher energy than those in FADH2. I can't find a (simple or otherwise) explanation of what a "high-energy" ...
3
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1answer
68 views

Lost track of the hydrogen in step 3 of the Krebs cycle

I'm trying to follow the Krebs cycle step by step, accounting for the number of hydrogens in each molecule before and after reactions. I've run into a problem starting from step 3. Isocitrate has ...
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0answers
85 views

Which of the following is the strongest oxidizing agent?

Which of the following is the strongest oxidizing agent? A) $\ce{I2}$ B) $\ce{Ag^2+}$ C) $\ce{Cu^2+}$ The answer is apparently B) but I think it has to be A) because it is the only non-metal which ...
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1answer
38 views

Balancing redox equation involving ethanol and dichromate ion [closed]

$$\ce{C2H6O(l) + Cr2O7^{2-}(aq) -> C2H4O2(aq) + Cr^3+(aq)}$$ Basically, I have written the half equations, but I have having trouble with converting ethanol to acetic acid ($\ce{C2H6O -> C2H4O2}$...
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0answers
27 views

Driving force of Galvanic cell

Work can be extracted from galvanic cell which has a negative Gibb's free energy. I was wondering what is the driving force of it: I would naturally think its the Gibb's free energy, but the gaps ...
3
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2answers
69 views

How do I prevent oxygen interfering when I prepare a FeCl2 solution from anhydrous FeCl2 powder?

I have a bottle of anhydrous $\ce{FeCl2}$ powder (from here; it is 98% pure and was kept in a glovebox after opening it for the first time to minimize reactions with oxygen) and want to make this into ...
1
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1answer
78 views

Acidic KMnO4 oxidizes H2S to S. Why doesn't the oxidation proceed further to sulfur oxide, sulfur dioxide or sulfur trioxide?

I have some idea about the question. I think it has to do with oxidation/reduction potentials but I am not able to find any resource for the exact values or how to make sense of them in this context. ...
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1answer
67 views

Will a gold coin react with an aqueous magnesium nitrate? [closed]

I really have no work to show, I don't even know how to approach answering this... so if someone can push me in the right direction, thanks. But I did have the idea that it might have something to do ...
-1
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1answer
48 views

How does Metol (4-(methylamino)phenol sulfate) react when developing black and white photos? [duplicate]

I know that during the development process the developing agents reduce exposed Ag ions to silver. But what happens to Metol which is one of the developing agents?
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3answers
82 views

How to balance the reaction between ethanol and chlorine using oxidation number method?

Balance the following chemical equation using oxidation number method: $$\ce{C2H5OH + Cl2 -> CHCl3 + HCO2- + Cl- + H2O}~\text{(In basic medium)}$$ Chlorine in $\ce{Cl2}$ is in oxidation state $0$ ...
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0answers
11 views

What does a sigmoidal and non-sigmoidal shape of a oxygen reduction reaction (ORR) voltammogram mean?

While testing materials for their ORR performance, one can encounter linear sweep voltammograms that have a well defined diffusion plateau and a good sigmoidal shape. On the other hand, the opposite ...
2
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1answer
102 views

How is indigo carmine used in Lowenthal-Permanganate titration as a redox indicator?

In a Lowenthal-Permanganate titration, cider tannins are quantified by titrating the cider with indigo carmine indicator and sulfuric acid against potassium permanganate. Tannins are antioxidants, so ...
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1answer
66 views

Redox and anode/cathode in lead acid battery

I have watch a video about lead acid battery and I am very confused about the way the half reactions are labelled. I have learned that oxydation is the loss of electron (so it's the half reaction with ...
-3
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1answer
60 views

How do I go about solving this question? [closed]

So I've studied Redox concepts but in the exam we are asked questions like these. How am I supposed to know what the reaction is going to be? How do I go ahead and assume what oxidation state it's ...
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0answers
28 views

How does the Benedicts Test work? [duplicate]

What exactly is the mechanism by which Benedict’s test works for reducing sugars? As I understand it the free hemiacetal groups on reducing sugars opens up and an aldehyde is formed, this is then ...
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0answers
48 views

What makes concentrated aqueous solutions of aluminium nitrate and aluminium chloride suitable to dissolve noble metals, specifically gold? [closed]

Aluminium nitrate is a strong oxidising agent and aluminium chloride acts as a Lewis acid. Also these solutions are claimed to have the abilities of aqua regia and therefore can dissolve noble metals. ...
1
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1answer
91 views

Why can't iodide be oxidised to iodate in acidic medium?

Even if we use a strong oxidising agent like 'permanganate ion in acidic medium' it doesn't help oxidise iodide to iodate, but a relatively weaker oxidising agent 'permanganate ion in alkaline medium' ...
3
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3answers
1k views

What is the equation for the reduction of water? [closed]

I'm a grade 12 student trying to understand redox reactions. What's the equation for the reduction of water? The back of my textbook says: $\ce{2H2O + 2e- -> H2 + 2OH-}$ I get that this makes sense,...
0
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0answers
20 views

When MnO2 acts as a catalyst to speed up the decomposition of H2O2 what does it actually do? [duplicate]

Everywhere I look it just states that $\ce{MnO2}$ acts as a catalyst but I have yet to find a simple explanation for what it actually does. What is the mechanism involved in simple terms?
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0answers
39 views

Write half-cell reaction for a battery

A primary battery has the reaction: $$\ce{2MnO2 + Zn + 2NH4Cl -> Mn2O3 + Zn(NH3)2Cl2 + H2O}$$ Write the half-cell reactions for the given equation. I am having trouble understanding how you know ...
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1answer
44 views

What (stored-as-solids) acids/liquids can clean corroded copper?

I'm looking for a liquid that can remove copper corrosion (oxides and basic carbonates - the black and green stuff) off copper piping. The corrosion will be located on the inside of the pipe, in hard-...
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0answers
45 views

What reaction would take place on an electrode in a secondary cell if it were charged and the other electrode removed?

I'm reading a book that covers the basics of electrical theory and I'm at a chapter that discusses the concept of a secondary cell. The author includes the redox reactions that take place in a primary ...
4
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0answers
34 views

After neutralizing a free radical, why don't anti-oxidants become free radicals themselves?

This is my understanding: A free radical is a molecule with a single unpaired electron. This molecule is highly reactive because it wants to steal an electron from another molecule (oxidation). Anti-...
0
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2answers
70 views

Calculating the cell potential of a half cell from two half cell equations [duplicate]

I understand the premise of the question and how to solve it but I don't quite understand why I'm a factor of 2 out: Construct a potential diagram (at $\mathrm{pH} = 0$) for the reduction of aqueous $...
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1answer
409 views

Oxidation of alcohols by Ceric Ammonium Nitrate

I have realized that reaction with ceric ammonium nitrate essentially results in coordination of alcohol with $\ce{Ce(IV)}$ and my teacher referred that we should be able to proceed it to form ketone ...
0
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2answers
251 views

Balancing a reaction where dichromate ion reacts with ethanol to give Cr(III) and carbon dioxide

I have only started to learn balancing redox reactions, and a recent question has me confused. The question is : Balance in both acidic medium and basic medium: $$\ce{Cr2O7^2- + C2H5OH -> Cr^3+ + ...
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1answer
550 views

Mechanism of reaction of benzenediazonium chloride with ethanol to form benzene and acetaldehyde

In my textbook, all that was told was that ethanol is a mild reducing agent and hence reduces BDC while oxidising itself. Is there any mechanism or am I just supposed to remember this like a redox ...
0
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1answer
37 views

Aluminum powder from aluminum sulfate?

I recently did the experiment where you drop a piece of iron in an aqueous solution of copper sulfate. After a while, the piece of iron gets coated with a fluffy coating of copper that can be dried ...
4
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2answers
388 views

Do both iodine and potassium iodide turn dark in the presence of starch?

I will do a titration to standardise a solution of sodium thiosulfate with potassium permanganate solution and potassium iodide solution. My book says that when the potassium permanganate solution ...
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1answer
66 views

What compounds given can oxidize Mn(2+) to MnO4(-)? [closed]

$$\ce{Mn^2+ Solution ->[reagent 'A'] MnO4^-}$$ The reagent '$\ce{A}$' can be (A) $\ce{Pb2O3 + \text{conc.} HNO3}$ (B) $\ce{K2S2O8}$. (C) $\ce{(NH4)2S2O8}$ (D) $\ce{K2SO4}$ All of the options can ...
7
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1answer
465 views

Do alkali metals react with ammonia to form hydrogen gas?

I was recently studying about s-block alkali metals and I found the following reaction: $$\ce{\underset{alkali\\ metal}{M\phantom{_y}} + \underset{solution}{$(x +y)$ NH3} -> \underset{ammoniated\\ ...
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3answers
103 views

The Curious Case of the equivalent weight

Please read the reference points given at the end. I understand the following about equivalent weight. Firstly it is given by, $Equivalent\:Weight= \frac{Molar\:Weight}{Valence\:Factor}$ And secondly, ...
1
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1answer
120 views

Cell voltage with different n factors

I’m a bit confused regarding cell potentials. If I have two half reactions each involving a different number of electrons, there are two ways I can see to calculate the net emf of their cell: Simply ...
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0answers
53 views

Oxidation of ethanol upon heating in a test tube

The diagram shows an experimental set-up which can be used in several different experiments. Which processes could be demonstrate by using the above apparatus? 1. Oxidation of ethanol (liquid X) 2. ...
-1
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2answers
469 views

Reaction of copper with nitric acid [duplicate]

When copper reacts with dilute nitric acid, $$\ce{3Cu + 8HNO3 -> 3Cu(NO3)2 + 2NO +4H2O}$$ while with concentrated nitric acid, $$\ce{Cu + 4HNO3 -> Cu(NO3)2 + 2NO2 + 2H2O}$$ As we see that with ...
2
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1answer
53 views

What is the influence of glass type on silver mirror making?

I'm considering the reaction wherein ionic silver (from the dissolved nitrate) is reduced by glucose in the presence of NaOH and forms a metalic silver layer on glass. Reading through several topics ...
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0answers
43 views

Why is copper(II) used a catalyst here instead of as an intermediate?

Photochromic glass, used for sunglasses darkens when exposed to bright light and becomes more transparent again when the light is less bright. The depth of color of the glass is related to the ...
1
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1answer
94 views

Why isn't chlorine reduced or nitrogen oxidised in the reaction between ammonium perchlorate and aluminium?

A space shuttle’s upward thrust came from the following reaction between aluminium and ammonium perchlorate. $$\ce{10 Al + 6 NH4ClO4 → 4 Al2O3 + 2 AlCl3 + 12 H2O + 3 N2}$$ Which statements about this ...
1
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2answers
87 views

Could an extremely strong reducing/oxidising agent attack nitrogen molecules? [closed]

Could a very strong reducing agent like lithium aluminium hydride or a very strong oxidizing agent like manganese heptoxide react with $\ce{N2}$? Usually when people talk about reactive substances ...
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0answers
39 views

Finding percent contamination of sulfur dioxide in air by redox reaction with iodine

I would really like some help with this problem. My work is at the bottom. I've tried multiple ways and have gotten the same answer for both, but for some reason the computer program won't accept the ...
1
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0answers
174 views

Preparing Hypochlorous acid from salt water

I am a school student and I want help with a project My aim: Preparing Hypochlorous Acid (Suitable for sanitation). I searched across the internet and found an article at https://www.hypochlorousacid....
0
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1answer
32 views

Different solutions in cyclic voltammetry

CV is usually used to monitor corrosion (from what I have learned) because, if it is a reversible reaction, we can see the cathodic and anodic peak in the voltammogram. I know that the scan rate ...
0
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0answers
64 views

Why cupric ion oxidises iodide to iodine

I have learnt in the qualitative analysis of cupric ions that upon treating its aqueous solution with excess $\ce{KI}$, triiodide ions are formed which can be further tested using starch. The ...
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2answers
58 views

Do reactions necessarily need to be redox in order to occur? [closed]

When l asked my teacher why the reaction between $\ce{S2O8^2-}$ and $\ce{Co^3+}$ did not occur, he said both were oxidising agents so their reaction would not be redox and thus the reaction would not ...
3
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0answers
429 views

Number of moles of acidified potassium dichromate required to liberate 6 moles of iodine from an aqueous solution of iodate ions

I came across this question in a recent exam I had taken: How many moles of acidified $\ce{K2Cr2O7}$ is required to liberate 6 moles of $\ce{I2}$ from an aqueous solution of $\ce{I-}$ ? So this is ...
0
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2answers
118 views

How to find number of moles of HNO3 behaving like acid in a redox reaction?

In the reaction $(1)$, how to find the number of moles of $\ce{HNO3}$, which is behaving like acid? The reaction is given as follows: $$\ce{Sn + HNO3 -> Sn(NO3)2 + NH4NO3 + H2O} \tag1$$ To find ...
2
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0answers
31 views

What is “protein redox conformation”?

From an article by Frye et al. [1]: Reduced glutathione (GSH) is the major intracellular redox buffer and is essential in free radical scavenging, redox homeostasis, maintenance of protein redox ...
3
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1answer
41 views

Side product obtained in reduction of cuprous oxide with carbon

So my book sates that in the extraction of cuprous oxide, the following reaction takes place. $$\ce{Cu2O + C -> 2 Cu + CO}$$ This makes sense to me, if it is seen as the following two reactions ...
0
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0answers
68 views

Sodium metal from electrolysis of molten sodium bisulfate?

My question is relatively straightforward. Can sodium metal be extracted from molten sodium bisulfate via electrolysis? I have done it before with molten sodium hydroxide, but there is such a small ...
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4answers
145 views

How do I balance this redox reaction? [closed]

The reaction given was $\ce{FNO3 -> O2 + F^- + NO3^-}$ (in basic medium) I've noticed that the atoms which have their oxidation numbers changed are the oxygen and the nitrogen atom (as the ...

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