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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2
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15k views

Oxidation number of nitrogen in KCN

How can one determine the oxidation number of nitrogen in $\ce{KCN}$?
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0answers
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How to prevent creation of piranha solution when conducting hydrogen peroxide titration?

I'm testing the activity of horseradish peroxidase (HRP) under different conditions by measuring the change in concentration of hydrogen peroxide substrate after a given amount of time. To stop the ...
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1answer
61 views

What would be the concentration of products in this calcium producing system?

I wanted to figure out a way to make calcium metal with potassium oxide. $\ce{K2O}$ undergoes disproportionation at $\pu{350-430 °C}:$ $$\ce{2 K2O -> K2O2 + 2 K}$$ Now, if I mixed in $\ce{CaO}$ (...
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3answers
180 views

Redox reactions redefined

I saw in my textbook (NCERT class 11 part2 chemistry) that oxidation is defined as gain of oxygen or more electronegative element by a substance. After it was redefined and said as oxidation ...
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How to determine an oxidation number of an atom in the compound, that has at least two elements, which are not hydrogen or oxygen?

Wiki says: [Oxidation state] is defined as the charge an atom might be imagined to have when electrons are counted according to an agreed-upon set of rules: The oxidation state of a free ...
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Why is hypochlorite a stronger oxidizing agent than other oxychlorides?

The reduction potentials of perchlorate, chlorate, chlorous acid and chlorine dioxide in acidic and basic solutions are listed in the table below: $$ \begin{array}{lcc} \hline \text{Oxychloride} & ...
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2answers
56 views

What happens when two galvanic cells are placed in series

I understand how a single galvanic cell works, and the relation of equilibrium and the Nernst equation. But this appears to contradict the higher voltage in a series configuration because it ...
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1answer
56 views

Making oxygen from iron oxide (aka rust) with sodium chloride?

I like videogames, and I've been playing a lot of "Oxygen Not Included" recently. It's not a perfect physics simulation, but it does appear to be realistic-ish (both Specific Heat and Thermal ...
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1answer
591 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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23 views

Where does the protons and electrons go in this redox reaction?

In the above oxidation reaction, does the 2 protons and electrons released get accepted by oxygen molecules? If not, where do they go? Appreciate all answers :)
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Will (3R,4S,5R)-1,3,4,5,6-pentahydroxyhexan-2-one tautomerise in nitric acid?

The following question was sent to me .The question is " Which of the following is A ?" The given answer was a,b,c Background If both ends of an aldose chain are oxidized to carboxylic acids the ...
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339 views

Reduction and oxidation in organic chemistry

What is the meaning of reduction and oxidation in organic chemistry? In general chemistry I learned an OIL RIG mnemonic, i.e. oxidation is loss and reduction is gain (of electrons). But what do we ...
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Difference between Lindlar and Rosenmund catalysts

Is there any difference between the Lindlar and Rosenmund catalysts? I've checked around, and it seems the same compounds are used to make both. Is there a difference in their reactivities or are they ...
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Chemical equation for oxidation of primary alcohol with acidified potassium permanganate

I have seen many sources describing the oxidation of alcohols with dichromate in great details; however, none or few gives a satisfactory description and explanation of the oxidation with acidified ...
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2answers
52 views

Reduction of ester in presence of ketone group

As there is no ring expansion I'm assuming that a carbocation should not form at ester carbon as it leads to ring expansion. But is there any an exception to it? Also the hint provided along with this ...
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1answer
77 views

Burning magnesium ribbon [closed]

I know that this might sound wrong but, in the reaction $$\ce{2 Mg(s) + O2(g) → 2 MgO(s) + energy}$$ isn't oxygen supposed to be oxidised as it has excess electrons $(\ce{O^2-})$ and can donate a ...
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2answers
4k views

What is purpose of sulfuric acid in iodine extraction?

I am trying to extract iodine from kelp following this guide here. It calls for sulfuric acid, but I don't see what this does do help the reaction. I thought the reaction was simply oxidizing iodide ...
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1answer
93 views

Does reduction/ oxidation take place separately at a half cell electrode?

In the redox reaction chapter, we learn that oxidation and reduction go hand in hand. The oxidising agent oxidises by accepting the electron released by the reducing agent and gets reduced in the ...
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1answer
52 views

How to oxidize tantalum? [closed]

I am interested in learning how to oxidize tantalum. I have seen some tantalum rings that the sellers say is a permanent smokey blackish color. But I've spoken to some people that say tantalum cannot ...
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1answer
32k views

What determines the strength of reducing and oxidizing agents?

The best reducing agents are located at the bottom left of the periodic table (low electronegativity) and the best oxidizing agents are located at the top right of the periodic table (high ...
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1answer
29 views

Fuel cell potential for the electrolysis of ammonia

I am trying to calculate the fuel cell potential for the electrolysis of ammonia with the following equation: ...
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1answer
63 views

Can antimony pentafluoride be made by adding hydrogen fluoride to antimony trifluoride?

I was looking at how the strongest acid was made and I found something I did not understand. On the Wikipedia page for antimony trifluoride it shows the production of $\ce{SbF3}$ using $\ce{HF}$: $$\...
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2answers
112 views

How do metals split the oxygen double bond during corrosion?

For a metal like $\ce{Mg}$ to corrode into $\ce{MgO}$, the double bond in $\ce{O2}$ must break. Since the dissociation energy of $\ce{O2}$ is 500 kJ/mol, using estimates from the Boltzmann ...
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electric potential of a redox reaction

I'm wanting to know how to figure out the electric potential of a redox reaction with the following half reactions: $$\ce{S (-II) - 8e- -> S (VI)}$$ $$\ce{4O(o) + 8e- -> 4O(-II)}$$ I can't find ...
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2answers
4k views

Equivalent weight in case of disproportionation reaction

We all know that $\text{Equivalent weight} = \frac{\text{Molecular weight}}{\text{n-factor}}$ However consider a reaction like: $\ce{Br2 + OH- -> Br- + BrO3- + H2O}$ where oxidation numbers of $\...
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Reaction between copper and silver(I) nitrate in aqueous medium

What is the reaction between $\ce{Cu}$ and $\ce{AgNO3}$ taking place in aqueous medium? The answer given was: "Only" oxidation of $\ce{Cu}.$ My concern is: how is only oxidation of $\ce{Cu}$ ...
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Can lead(II) oxidize tin metal in aqueous solution?

According to my textbook, element $\ce{X}$ can oxidize element $\ce{Y}$ if $\ce{X}$ was lower in the activity series. Lead is lower than Tin in the activity series table in the textbook, but the ...
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2answers
46 views

Is this balanced redox equation correct? [closed]

I'm trying to balance an equation using oxidation numbers $\ce{MnO4^- + H+ + Cl- -> Mn^2+ + Cl2 + H2O}$ my suggestion: $\ce{MnO4- + 8H+ + 5Cl- → Mn^2+ + 2.5Cl2 + 4H2O}$ the 2.5 $\ce{Cl2}$ is ...
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1answer
247 views

Reason of dissociation of water molecule in electrolysis

$\ce{H2O}$ molecule is dissociated into $\ce{OH-}$ and $\ce{H+}$ ions on reduction at the cathode in electrolysis. But what happens at the atomic level to $\ce{H2O}$ that proton and hydroxide ions get ...
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1answer
47 views

Why does hydrogen burn spontaneously in fuel cell at room temperature?

It's well known that if you mix $\ce{H2}$ and $\ce{O2}$ in ambient conditions, the $\ce{H2}$ will be stable indefinitely, and will only react with $\ce{O2}$ to form water when ignited by a flame. The ...
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1answer
35 views

Redox titration or iron(II)

The concentration of $\ce{Fe^2+(aq)}$ can be determined by a redox titration using A. $\ce{KBr}$ B. $\ce{SnCl2}$ C. $\ce{KMnO4}$ (basic) D. $\ce{KBrO3}$ (acidic) Can anyone please ...
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1answer
88 views

Reaction of potassium with water

In general, when we put potassium into water, it will produce potassium hydroxide and hydrogen: $\ce{2K + 2H2O ⟶2KOH + H2}$ However isn't the following reaction also possible? $\ce{2K + H2O ⟶K2O + ...
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2answers
2k views

How to write equations for a reaction of metals with water

Please write two equations for reacting lithium with water and barium with water. Make sure to add the states of matter after each compound. Currently, for lithium I have the equation $$\ce{2Li(s) +...
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3answers
45 views

Can Iron(III) oxide oxidize elemental iron in a nitrogen environment under room temperature without any catalysis? [closed]

Will there be electron transfer to allow this process to happen: $\ce{2 Fe(III) + Fe(0) -> 3 Fe(II)}$
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3answers
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Reaction mechanism of combustion of hydrogen

After a discussion about the usefulness of hydrogen fuel for cars with a friend of mine, I wondered what the reaction mechanism for combustion of $\ce{H2}$ was. I only study (well almost) organic ...
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0answers
43 views

Reaction of DIBALH with alkyl cyanides

I was recently studying reactions involving DIBALH (diisobutyl aluminium hydride) and saw that it's reaction with alkyl cyanide yielded R-CH2NHOH according to Jerry March whereas in Solomons the ...
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1answer
52 views

What are the half reactions for the redox reaction between SO2 and iodine?

What are the half reactions for the redox reaction between $\ce{SO2}$ and iodine? The relevant chemical equation: $$\ce{ SO2 + H2O + I2 -> H2SO4 + 2HI}$$ This is what I think it is, not sure if ...
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1answer
177 views

Reaction between copper(II) iodate and iodide

I was attempting the following question from IChO 1989, which involved balancing of redox equations. One may just expect this to be a typical iodate-iodide redox reaction, usually employed in ...
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2answers
240 views

Leaching of copper using zinc

Why can we not use zinc for extracting copper from a solution containing $\ce{Cu^2+}$ ions even though it is a better reducing agent than $\ce{Fe}$? I am studying metallurgy and I cannot understand ...
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0answers
24 views

Electric potential of a redox reaction (without solids)

I need someone to help me with a problem: We have a solution which is $\pu{0.1 M}$ of $\ce{KMnO4}$ and $\pu{0.1 M}$ $\ce{Fe^2+}$ and has $\mathrm{pH}=0$. Given the electrical reduction potential of ...
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2answers
6k views

Determine the oxidation number of sulfur in SF6

I've just started learning about redox chemistry and oxidation numbers. I can work out most of the oxidation number questions, but I don't know how to determine the oxidation number of sulfur in $\ce{...
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39 views

Can a cation form a bond with only the oxygen in hydroxide ion?

$$\ce{Al2O3 + 2 NaOH → 2 NaAlO2 + H2O}$$ In this reaction between an amphoteric oxide and a base, I do not understand how $\ce{Al}$ makes a bond with oxygen atoms since the water is found in the ...
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1answer
67 views

Why do Cu⁺ ions spontaneously form copper metal and Cu²⁺ ions in solution?

The standard electrode potentials for three reactions involving copper and copper ions are: $$ \begin{align} \ce{Cu^2+(aq) + e- &-> Cu+(aq)} &\quad E &= \pu{+0.15 V} \\ \ce{Cu^2+(...
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3answers
4k views

What is the strongest oxidising agent?

I searched for the strongest oxidising agent and I found different results: $\ce{ClF3}$, $\ce{HArF}$, $\ce{F2}$ were among them. Many said $\ce{ClF3}$ is the most powerful as it oxidises everything, ...
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0answers
40 views

Why does the following “Battery” experiment work?

I did the following experiment: Experimental setup: Two electrodes (one made out of Iron,the other made out of Copper) are put into a (bluish) Copper(ii) sulfate lotion. Then, one connect a ...
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1answer
374 views

What do the half-reactions need to be for balancing a redox reaction in an acidic medium?

Balance the following reaction: $$\ce{CuS + SO4^{2-} -> CuO + SO2}$$ Below, the number mentioned in the parenthesis is the oxidation number of sulfur. I have found out that the oxidation half-...
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1answer
45 views

Disproportionation of 2 KO₂ + 2 H₂O → 2 KOH + H₂O₂ + O₂

How is the following reaction a disproportionation reaction? $$\ce{2 K\overset{-1/2}{O}_2 + 2 H2\overset{-2}{O} ->2 KOH + H2\overset{-1}{O}_2 + \overset{0}{O}_2}$$ In this, the OS are $-1/2$, $-2$...
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3answers
30k views

Why is the reaction between potassium permanganate and hydrogen peroxide spontaneous?

When hydrogen peroxide is mixed with potassium permanganate, oxygen gas and water vapour are formed, according to the reaction (source): $$\ce{2MnO4- + 3H2O2 -> 2MnO2 + 2H2O + 3O2 + 2OH-}$$ This ...
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0answers
13 views

Nitrate reaction with iron minerals

I am trying to find literature or an answer to what happens to nitrate as it comes in contact with iron oxides. Does the nitrate get reduced to ammonium in all cases of iron(II/III) oxides? What is ...
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2answers
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Two cells are connected in series. If x g of silver are deposited in cell 1, what volume of oxygen is given off in cell 2? [closed]

I got the answer correct but I'm pretty sure my methodology was wrong. How would you solve such a question?