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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0answers
76 views

Mechanisms of Birch and Bouveault-Blanc Reductions

The question is all about the sequence of a possible Birch- and Bouvault-Blanc-Reduction in this exemplary substrate. With which reduction the mechanism begin? My first attempt was to classify the ...
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1answer
72 views

Working principle of simple chemical cells

I have just learnt about simple chemical cells but I have no idea how to determine which cells will work and which will not and the working principle of those cells. I know that a chemical cell with $...
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607 views

What are the products formed when nitrogen dioxide reacts with water?

I've seen two different equations for the reaction of nitrogen dioxide with water: $$\ce{2NO2 + H2O -> H+ + NO3- + HNO2}$$ and $$\ce{3NO2 + H2O -> 2H+ + 2NO3- + NO}$$ Are both of these ...
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72 views

How to balance this redox reaction taking place in a basic medium?

How to balance this reaction which is taking place in a basic medium? $$\ce{Al + MnO4- -> MnO2 + Al(OH)4-}$$ My Attempt Reduction half reaction: $$ \begin{align} \ce{4 H+ + MnO4- + 3 e- &-&...
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1answer
62 views

Calculating the standard reduction potential for the oxidation of water

I was working with Latimer and Frost diagrams for oxygen when I came across what seems to me a contradiction. From the Latimer diagram for oxygen below, we know the standard reduction potential for ...
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1answer
83 views

Half-Reactions of Hydroxide [closed]

The following is the equation I have: $$\ce{Ca(s) + 2H2O(l) -> Ca(OH)2 v + H2 ^}$$ I am tasked to write the half-reaction equations for both the oxidation and/or reduction process. So, currently ...
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127 views

Abnormal reaction of grignard reagent

My book states that: When isopropyl magnesium bromide is added to diisopropyl ketone, the expected tertiary alcohol is not obtained; instead the secondary alcohol; diisopropyl carbinol is obtained ...
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1answer
55 views

Do redox reactions always contain pure elements? [closed]

According to a video by the Organic Chemistry Tutor, a quite well-known chemistry channel on YouTube, you can easily identify a redox reaction by seeing if there are atoms in their elemental states on ...
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1answer
44 views

Does berylium gain or lose electrons?

Does beryllium want to gain or lose electrons? I know it has 4 protons, 2 valence electrons, and it will gain or lose 2 electrons, but what is it?
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2answers
359 views

Why won't removing the salt bridge cause the battery to recharge?

If I understand correctly, the salt bridge in a battery is used to move positive ions towards the side that is becoming more negative, and negative ions towards the side that's becoming positively ...
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How does copper reduce dilute nitric acid to nitric oxide and concentrated nitric acid to nitrogen dioxide?

Here are the 2 equations: \begin{align} \ce{3Cu + 2NO3- + 8H+ &<=> 3Cu^2+ + 2NO + 4H2O} & E &= 0.62~\mathrm{V}\\ \ce{3Cu + 2NO3- + 4H+ &<=> 3Cu^2+ + 2NO2 + 2H2O}& E &...
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In a galvanic cell where the two electrodes are in the same electrolyte solution, why do reduction and oxidation occur separately?

In a certain book, I was presented with the following solution: An iron nail is attached by a piece of wire to a magnesium ribbon, and the iron and magnesium are placed into the same container, with ...
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Half-reaction for ammonium nitrate comproportionation into dinitrogen monoxide.

Ammonium nitrate comproportionates into dinitrogen monoxide in the following reaction: $\ce{NH4+ (aq) + NO3- (aq) -> N2O(g) + 2H2O (l)}$ I attempted to write the half-reactions by calculating ...
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3answers
244 views

Balancing the Redox reaction by Half reactions

I'm having trouble balancing this reaction using half reactions: $$\ce{I2 + KOH -> KI + KIO3 + H2O}$$ I so far know that Iodine is reduced when it forms KI(oxidation no decreases from 0 to -1) and ...
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1answer
125 views

How to apply oxidation numbers in the reaction to form hydrogen peroxide from a superoxide?

In the following reaction: $$\ce{2O2- (aq) + 2H+ (aq) <=> H2O2 (aq) + O2(g)}$$ I see where some oxygen atoms have lost electrons, but I do not see what has gained electrons. On the reactant ...
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Why does standard reduction potential get multiplied by the change in oxidation state and not by the number of electrons transferred?

The whole basis of Frost diagrams is to have a graphical representation of the Gibbs free energy of formation ($\Delta{G}_{f}$) of different oxidation states of an element using the proportional ...
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88 views

Manganese (II) oxidation by air

I am studying the reaction of dissolved dioxygen with manganese(II) hydroxide for the Winkler method: 2Mn(OH)2(s)+O2(aq)⟶2MnO2(s)+2H2O(l) The ...
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1answer
650 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
2k views

Is there a database which give reaction constant?

For instance, I have a chemical reaction like : $$\ce{Fe^{2+} + $0.5$O2 + H^{+} ->Fe^{3+} + $0.5$ H2O}$$ And I would like to use Action-Mass law, but I need to have equilibrium constant for this ...
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4answers
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Why is Cr(2+) a stronger reducing agent than Fe(2+) in water?

According to me, $\ce{Fe^{2+}}$ should be a better reducing agent because $\ce{Fe^2+}$ - after being oxidized - will attain a stable $\ce{d^5}$ configuration, whereas $\ce{Cr^2+}$ will attain a $\ce{d^...
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1answer
134 views

Balancing the equation for the preparation of dichromate from chromite ore

$\ce{FeCr_2O4 + Na2CO3 + O2 -> Na2CrO4 + Fe2O3 + CO2}$ I have tried balancing it by writing the reduction and oxidation half equations viz. : $\ce{2Fe^{+II}Cr_2^{+III}O4 -> 4Na2Cr^{+VI}O4 + ...
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1answer
57 views

Using a significantly large metallic sphere, could we draw out the electrons from the negative terminal of a battery?

I've pored over many articles on electrochemical cells, and I understand that on the oxidation side of a zinc-copper Daniell cell, the anode is highly negatively charged because zinc participates in ...
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1answer
193 views

Balancing the reaction of nitric acid with zinc using oxidation number method

In a previous question, there was confusion relating to what this "oxidation number method" is. So I will illustrate that before my question. Write the skeleton equation representing chemical ...
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1answer
79 views

Balancing Redox Reactions (oxidation number method)

I'm confused about balancing redox reactions using the oxidation number method. I know that in order to get my coefficients for the two reactants I need to find the simplest whole number. However, ...
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1answer
43 views

Troubleshooting electrochemical batteries

For my science classes, I have built multiple types of electrochemical batteries utilizing oxidation-reduction reactions, and I have demonstrated that they each produce potential difference across the ...
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1answer
118 views

What should be the reaction between lead oxide and dilute sulfuric acid?

I know for a fact that dilute $\ce{H2SO4}$ is a non-oxidizing acid which makes it a reducing agent. I also know for a fact that $\ce{PbO2}$ is a strong oxidizing agent. So, I thought Redox reaction ...
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2answers
3k views

How can titanium burn in nitrogen?

I was going through the properties of titanium when a certain thing caught my eye: It was the reaction of burning of titanium in nitrogen. I was astonished to read it as I knew that neither is ...
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2answers
12k views

What does oxidizing strength mean?

What does oxidizing strength mean? Does it mean the strength of a oxidation agent that is needed to oxidize the reduction agent, or does it just mean the tendency of a substance to lose electrons (...
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1answer
11k views

Why is difluoride a stronger oxidizing agent than dichloride? [closed]

I am preparing for a chemistry olympiad and I am stuck with the question that why $\ce{F_{2}}$ is stronger oxidizing agent than $\ce{Cl_{2}}$.
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1answer
683 views

Why heating up things before H2C2O4 &KMnO4 titration? [closed]

In my school, there is a redox titration between H2C2O4 being titrand and KMnO4 being titrant. After adding H2SO4 to the acid to give an acidic medium for redox, the whole mixture inside the conical ...
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Why don't everyday things burn?

Ok, so I learned about the equilibrium constant. Now, I've seen that the equilibrium constant of burning is extremely small $(K \ll 1)$. here, I have a question. you see, $K$ is still NOT 0, which ...
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1answer
66 views

What substance consumes oxygen from atmospheric air [closed]

I'd like to find an economical substance that will consume oxygen from a container. Steel wool comes to mind but I don't have an intuition how feasible it would be. The chamber is 5 gallons in size ...
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What is the electrode potential at the equivalence point if concentrations of titrant and titrand are going to be zero?

Let's assume that the titrand is $\ce{Fe^2+}$ and the titrant is $\ce{Cr2O7^2-}$. Then $$E = E^\circ_\ce{Fe^{2+}/Fe^{3+}} - \frac{RT}{nF}\ln\frac{\ce{[Fe^{2+}]}}{\ce{[Fe^{3+}]}}$$ $$E = E^\circ_\ce{...
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1answer
117 views

Why does the addition of oxygen render materials colourless? [closed]

In our book, it is mentioned that $\ce{H2O2}$ (hydrogen peroxide) is used as a bleaching agent because of its oxidizing nature: \begin{align} \ce{H2O2 &-> H2O + [O]}\\ \ce{\text{coloured ...
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1answer
242 views

How to calculate the concentration of lead(II) liberated from lead(IV) oxide under acidic conditions? [closed]

What is the concentration of $\ce{Pb^2+}$ in a lake that has a pH of $6.0$ and is in equilibrium with $\ce{PbO2(s)}$ and atmospheric oxygen? \begin{align} \ce{PbO2(s) + 4H+ + 2e- &-> Pb^2+ + ...
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1answer
467 views

Why does chlorine oxidise iron to iron(III), not iron(II)?

I was asked to predict the product of the reaction between iron metal and chlorine gas: $$\ce{Fe +Cl2->} ?$$ The product here is supposed to be $\ce{FeCl3}$. But how would we know if the product ...
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1answer
6k views

Why do gummy bears explode when added to hot potassium chlorate?

This link shows that a gummy bear explodes when in contact with heated potassium chlorate, $\ce{KClO3}$. But what in a gummy bear creates this reaction? Also, do other foods (fruit, icing sugar...) ...
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Why is nitric acid such a strong oxidizing agent?

In my teaching-lab experiments I've seen that nitric acid solutions are able to facilitate the dissolution of metals such as silver, even though they are more active than hydrogen. Does anyone know ...
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1answer
65 views

Can all oxidizing agents be used interchangeably in organic chemistry reactions? [closed]

Butanol can be oxidized with pyridinium chlorochromate (PCC) yielding butanal. If the case is that butanol can be oxidized with PCC, can it be oxidized with CrO3, H2SO4, HNO3, OsO4, and other ...
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Reduced Graphene Oxide (RGO) Conductivity vs Everything Else

Reduced Graphene Oxide (RGO), is the reduced version of Graphene Oxide (GO). Both RGO & GO are easily manufactured when compared to the complex process used to manufacture the 'atom-thick' ...
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1answer
39 views

What drives the redox reactions in a standard hydrogen electrode?

In this video, the SHE half cell has two redox reactions occurring i.e. $$\ce{2H+ (g) + 2e- <=> H2 (g)}\\ \ce{H2 (g) <=> 2H+ (g) + 2e-}$$ But how can a single half cell initiate the two ...
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1answer
2k views

Alcoholic potassium permanganate for oxidation

A question in my textbook: Though alkaline and acidic $\ce{KMnO4}$ are both oxidizing agents, in the manufacture of benzoic acid from toluene, we only use alcoholic $\ce{KMnO4}$ as an oxidant. Why? ...
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3answers
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Why reduced atoms are more energetic?

For example, in glycolysis, $\ce{NAD+} $ is reduced to $\ce{NADH}$ and then it's more energetic. Why adding electrons to an atoms gives it more energy?
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2answers
185 views

Redox reaction terminology

In the case of this redox reaction: $ \ce{ Cu SO_4 + Zn → Zn SO_4 + Cu} $ Is it correct to say that the sulfate reduces to the zinc? Or is it the whole molecule that is reducing? Or just the copper? ...
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2answers
4k 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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2answers
764 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
288 views

Does hydrogen peroxide in basic medium only give oxygen gas on oxidation?

Does hydrogen peroxide on oxidation gives oxygen gas only in basic medium? I thought that was true but I read about these reaction of $\ce{H2O2}$ in acidic medium: $$\ce{2MnO4- + 6H+ + 5H2O2 -> ...
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1answer
1k views

How can zinc metal still be present after the reaction? [closed]

A $\pu{15.8 g}$ strip of zinc metal was placed in $\pu{100 ml}$ of silver nitrate. When the reaction was complete, the strip of zinc had a mass of $\pu{13.1 g}$. What was the concentration of the ...
2
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1answer
621 views

Why can't sulphate ion be discharged in the anode of electrolysis?

Given that there is an aqueous solution of sulfuric acid ($\ce{H2SO4}$), $\ce{2H+}$ is reduced in the cathode and $\ce{OH-}$ is reduced in the anode. Why is $\ce{OH-}$ preferentially discharged over $\...
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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 ...