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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.

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How to write a reaction that you have never seen? [closed]

I have been studying chemistry for a while but I feel a total noob about it, so please be clear when answering. I was studying and I encountered this exercise: Write the reaction between copper ...
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1answer
61 views

How does the redox of a battery happen? [closed]

I tried to understand how does a battery work. After doing some research, I knew chemical reactions inside are key. But when I came across the reactions inside a zinc carbon battery, almost all ...
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1answer
340 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 $\...
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1answer
2k views

Why does the reaction between potassium permanganate and oxalic acid result in a yellow/brown solution?

The reaction between potassium permanganate and oxalic acid is a redox reaction and produces $\ce{Mn^2+}$ ions, the final solution however goes yellow/brown. If $\ce{Mn^2+}$ ions are colourless, and ...
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1answer
65 views

Writing disproportionation half reactions

Question Write the half equations for the following reaction: $$\ce{3OCl- -> 2Cl- + ClO3-}$$ I know that $\ce{Cl}$ is reduced from an oxidation state of 1+ to 1- (in $\ce{Cl-}$) and is ...
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1answer
3k views

Reaction of sulphur dioxide with solution of potassium permanganate

Solution of $\ce{KMnO4}$ is decolorised by $\ce{SO2}$. Is this due to the reducing nature of $\ce{SO2}$ or acidic nature of $\ce{SO2}$ ? I encountered following two explanations. While first one ...
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1answer
193 views

What's the role of sodium carbonate and hydrochloric acid for the neutralization of disaccharides into monosaccharides?

A couple of days ago we conducted the following experiment at school: Add 5mL of an aqueous solution of sucrose ($\ce{C6H22O11}$) to 1mL of concentrated hydrochloric acid and heat it for 10 minutes....
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1k views

H2O2 + H2SO4 + 2 KI solving the equation

The products I got are following H2O2 + H2SO4 + KI and I found after some research online that the equation should be Now I tried to work this out various ways but always end up like this (see ...
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0answers
156 views

What's the reaction mechanism for the oxidation of primary alcohols (e.g. ethanol) to carboxylic acids using acidified KMnO4?

I've seen mechanisms for $\ce{MnO4-}$ in base reacting with primary and secondary alcohols to oxidise them, but what about $\ce{MnO4-}$ in acid? All the ones I've found have either been referring to ...
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1answer
218 views

Why is antimony oxide used as a flame retardant?

What is the mechanism of action of antimony oxide as a flame retardant? Is this to do with radical absorption?
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430 views

Does Sn/HCl reduce the carboxylic group of benzoic acid?

I googled, but couldn't find any proper answer. As far as i know, $\ce{Sn/HCl}$ is a mild reducing agent and reduces a $\ce{NO2}$ group of nitrobenzene into $\ce{NH2}$. But does it reduce the $\ce{...
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58 views

Is it possible to produce hydrogen sulfide with tap water and activated carbon or CuZn?

Please note I'm a bit out of my depth with chemistry. The situation: I have a KDF/GAC water filter that defies logic and releases $\ce{H2S}$ (assuming it by smell/taste) in the water after filtration....
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1answer
89 views

Electrolysis of Potassium Iodate/Hydrogen Peroxide in Briggs-Rauscher Oscillation

I would like to investigate the effect of adding a voltage in the Briggs-Rauscher oscillation reaction. I will examine the oscillations visually. The ingredients I will use include potassium iodate, ...
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2answers
1k views

Reaction of sulphur and nitric acid

I would like to ask a question about Sulfur in the reaction with Nitric Acid, $\ce{HNO3}$ to produce Sulfuric Acid, $\ce{H2SO4}$ I read that as Nitrogen and Sulfur are reduced and oxidised ...
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1answer
346 views

Why is the following reaction not considered a redox reaction?

The following question appeared in the Cambridge International AS and A level Chemistry Coursebook: Choose from redox, substitution, elimination, addition and hydrolysis to give the type of ...
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2answers
2k views

Why is hypophosphorous acid (H3PO2) a strong reducing agent?

Why is hypophosphorous acid $(\ce{H3PO2})$ a strong reducing agent? the oxidation state of phosphorous in $\ce{H3PO2}$ is $+5$, as hydrogen and oxygen both are more electronegative than phosphorous, ...
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0answers
81 views

What exactly is the mechanism of “nascent hydrogen”? [closed]

I put the quotes because Wikipedia says it's an outdated theory. What exactly happens when nitrobenzene is converted to aniline using $\ce{Sn/conc HCl}$? According to a few books which haven't been ...
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1answer
48 views

How to calculate the electrochemical potential of a cell using known half-cell potentials?

What is $E^\circ$ for the half-reaction representing the oxidation of $\ce{HOCl}$ to $\ce{ClO3-}$ given the equations below? \begin{align} \ce{ClO3- +6 e− + 6 H+ &= Cl− +3 H2O},& E^\circ &...
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2answers
463 views

Reaction of Halogens with water

The reaction of fluorine with water is very different from that of chlorine with water. $$\ce{2F2 + 2(H2O)->O2 + 2HF}\tag1$$ $$\ce{Cl2 + H2O ->HCl + HOCl}\tag2$$ I want to understand two main ...
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1answer
53 views

Prevent/Slow down oxidation of organic material

I'm having the hobby to draw paintings with the tea I drink trough the day. Usually I pour a tablespoon of the hot tea away, wait until it dries and gets more concentrated, so the colour is more ...
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1answer
281 views

Trend in reducing property of dioxides

I am not sure of the explanation for the following statement: The reducing property of dioxides of group 16 elements decreases from $\ce{SO2}$ to $\ce{TeO2}$. Is the statement valid? If yes, how ...
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1answer
75 views

Can oxidation of hydrogen happen in room temperature? [duplicate]

Here is my explanation about the reaction between hydrogen or methane and oxygen. Hydrogen molecules and oxygen molecules can collide sucessfully and react if they have enough energy. In room ...
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1answer
52 views

Simplest way to convert glucose into water and carbon dioxide other than burning?

What is the simplest pathway from glucose to $\ce{H2O}$ and $\ce{CO2}$, such that all reactions happen in aqueous solution with pH between 5 and 8, temperature is in range between 0 and 35 °C, no (...
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0answers
64 views

Rationalise the Relative Reactivity of Borane and DIBAL as Reductants

In Clayden's Organic Chemistry (Second Edition) it is written that borane is useful in chemoselectively reducing the most nucleophilic carbonyl to its corresponding alcohol. It is later said that ...
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1answer
44 views

(RedOx) How should i continue?

i'm stuck on a redox, currently in the oxidation semireaction. The reaction is: $\ce{B + NaOH = NaBO2 + H2 + Na2O}$ The reduction semi reaction is: $\ce{B = NaBO2}$ And i balanced it like this: $\...
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2answers
421 views

How does an acid prevents or discourges oxidation of iron?

In the titration of $\ce{KMnO4}$ with Mohr's salt, I have learned that sulphuric acid prevents oxidation of $\ce{Fe^2+}$ to $\ce{Fe^3+}$ in the solution before the actual titration. How does the acid ...
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0answers
3k views

Why Mohr's salt and not FeSO4 in titration? [closed]

During titration of $\ce{KMnO4}$, we use Mohr's salt instead of ferrous sulphate salt to prepare the standard salt solution. Is it done to prevent oxidation of $\ce{Fe^2+}$ to $\ce{Fe^3+}$ before the ...
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0answers
43 views

Can someone please help me understand something about cathodic protection

Good day, can someone please have a look at the following paragraph. "Cathodic protection is an attempt to reduce or eliminate corrosion of a metallic structure by ensuring it acts as the non-...
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1answer
220 views

Is the reaction of SiC and H2O a redox reaction?

In the reaction: $$\ce{SiC + 2H2O <=> SiO2 + CH4}$$ The oxidation state of Si is +4 in both SiC and SiO2, while the oxidation state of carbon is -4 in both SiC and CH4 (confirmed by this). Here ...
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0answers
437 views

Why do disproportionation reactions take place?

I want to know what are the conditions when disproportionation reaction is feasible. Is it just because of stability factors or it has other dimensions to it. As an example: $$\ce{3HNO2 -> HNO3 + ...
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0answers
365 views

Is sodium sulfide a reducing agent or an oxidizing agent?

Is $\ce{Na2S}$ used as a reducing agent or as an oxidizing agent? I had a disagreement with my classmates at this particular topic, because I think it is both of them. The answer which was considered ...
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2answers
114 views

Calculate the cathode electrode potential in this redox reaction

In this problem I'm asked to calculate the electrode potential of the magnesium electrode ($E_{Mg^{2+}/Mg}$) given the red-ox reaction:$$\text{Mg(s)}+2\text{Ag}^+(10^{-2}\text{M})\leftrightarrow 2\...
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0answers
85 views

What exactly is an “electron-sponge”?

What exactly an "electron-sponge" [behavior/action/property/system] nickname is, and what makes a material an "electron-sponge" (preferably, quantitatively)? From what I found, it's typically a ...
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1answer
43 views

Balancing other atoms in a redox reaction using half reaction method

I have this balanced redox reaction: $$\ce{2H2O + 8Al + 3NaNO3 + 5NaOH -> 3NH3 + 8NaAlO2}$$ I think its unbalanced form should be (I guess water added to balanced it) $$\ce{Al + NaNO3 + NaOH -> ...
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1answer
39 views

Determining the theoretical mass of gas produced through the process of electrolysis

I have a question that has been stumping me for quite some time. I wish to calculate the mass of gas that is produced from varying concentrations of salt (NaCl) through the process of electrolysis. I ...
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1answer
34 views

Reaction characteristics of alkaline battery [closed]

I'm currently struggling with understanding why electrochemical reactions take place the way they do. For example, in an alkaline-manganese battery manganese-dioxide is getting reduced by reacting ...
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0answers
25 views

Relationship between Yield and Applied Potentials

This question revolves around this question from Atkins' Chemical Principles 5th ed., Chapter 13, Question 13.116: Consider the electroplating of a metal $+1$ cation from a solution of unknown ...
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1answer
339 views

What is equivalents per mole?

Which has maximum number of equivalents per mole of the oxidant? $$ \begin{align} \ce{MnO4- + H2O2 &-> Mn^2+ + O2}\tag{i}\\ \ce{Cr2O7^2- + Fe^2+ &-> 2 Cr^3+ + Fe^3+}\tag{ii} \end{align}...
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1answer
2k views

How to balance equation of alcohol oxidation with potassium permanganate?

R-CH2OH(aq) + MnO4{-}(aq) --> R-COO{-}(aq) + MnO2(s) The above equation is the oxidation of a primary alcohol. The media is neutral to start out with, but the product will be basic*. From what I ...
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1answer
43 views

Does silver oxidise in a pH 1 solution?

Consider submerging a plate of pure silver in a solution with $\mathrm{pH} = 1$. Does the redox reaction with hydrogen happen spontaneously? The composition of the solution is not given. My ...
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2answers
139 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. ...
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1answer
42 views

Redox - concentration cell

I'm studying galvanic cells and I've found a demonstration that lead me to an impossible result, so there must be a mistake, but I can't find what it is. My problem is about concentration cells made ...
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1answer
164 views

Is it a redox reaction if the oxidation state of the element has changed only in one of the products?

I’m not sure on which elements to compare to ensure that this is a redox reaction: $$\ce{2 H2SO4 (aq) + 2 NaBr (s) -> Br2 (l) + SO2 (g) + Na2SO4 (aq) + 2 H2O}$$ I’m trying to indicate whether ...
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2k views

Oxidation of naphthalene with KMnO4

What is the product when naphthalene is oxidized by alkaline (or acidic) solutions of $\ce{KMnO4}$? Some possible reactions show up in a google search, but they have no references: Naphthalene to ...
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1answer
400 views

Why isn't hydration an oxidation reaction?

http://chemistry2.csudh.edu/rpendarvis/OxRed.html states, Addition or removal of water does not involve, by itself, an oxidation or a reduction reaction. The addition of water to an aldehyde to ...
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1answer
33 views

Metal and reactions with different temperatures of water

I knew that in warm water magnesium forms $\ce{Mg(OH)2}$ and $\ce{H}$ gas, and in steam it forms $\ce{MgO}$ and $\ce{H}$ gas (this is also the case for metals lower down the electrochemical table). ...
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1answer
61 views

What are the following equations called?

Our teacher was writing out the following ways of expressing redox and she used a particular term for what these equations are called. When we write out the following what is this called? Its a way to ...
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0answers
184 views

In a galvanic cell, do the ions from half cell move into the salt bridge?

I know that ions from salt bridge move into the half cell in order to maintain electrical neutrality. But in my book it's also given that ions move from half cell into the salt bridge. For example, ...
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0answers
965 views

reduction of Fe3+ to Fe2+ in (slightly) oxidated FeCl2 solution

I am doing some experiments with Fe2+ to create nano crystals (in aqueous solution) but Fe3+ is messing with my experiment. I was planning to use some Zinc (which I'll need to order from VWR or Sigma) ...
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0answers
39 views

Mechanism of hydrogen evolution on metal-oxide electrodes

I am looking into the mechanism of different electrocatalytic reaction in acidic media on metal-oxide electrodes. Reduction of on such electrodes generally happens with the help of electrons from ...