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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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What is brown/red precipitate in battery acid

I am working on recovering some lead acid batteries that have lost some of their capacity. I drained all of the sulfuric acid out and there was an awful lot of brownish red precipitate in it. My ...
Alan's user avatar
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2 answers
119 views

Why does the reaction "pause" when the battery is not connected to a circuit? (or does it?)

The general set up, In an alkaline battery, the negative electrode is zinc (Zn) and the positive electrode is manganese dioxide ($\ce{MnO2}$). The alkaline electrolyte of potassium hydroxide (KOH) At ...
Reuben's user avatar
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0 votes
1 answer
119 views

How do I explain that voltage decreases when increasing the concentration of the cathode in a voltaic cell?

I just finished a lab experiment in which I built a voltaic cell with copper (II) sulphate and zinc sulphate. My experiment was to identify the correlation between the concentration of copper (II) ...
Night's user avatar
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0 votes
2 answers
194 views

What is meant by 'as Cl2'

I feel like I'm over thinking this one, but think I need a confirmation (and quantified example) to put my confusion to bed. I'm more a mechanical than chemical background but trying my best. I really ...
Kuhrta's user avatar
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0 votes
0 answers
45 views

When forming an epoxide with m-CPBA, what happens when we wash our mixture with Na2S2O4?

The m-CPBA is reduced by the $\ce{S2O4^{2-}}$, but why does it leave the mixture then? Why does the reduced m-CPBA leave with the oxidised $\ce{S2O4^{2-}}$?
Dlouna.J's user avatar
5 votes
2 answers
362 views

Using potassium dichromate and sulfuric acid to clean test tubes after Tollens’ test

We had an experiment at school to find out the biomolecules contained in the different foodstuffs. After doing Tollens’ test which turned out to be positive, our teacher instructed us to clean the ...
Harikrishnan M's user avatar
-2 votes
1 answer
95 views

is alkyl halide turning into alkene reduction or oxidation? [closed]

Is the reaction of 2-iodobutane turning into but-2-ene reduction or oxidation reaction?
blob of water's user avatar
4 votes
2 answers
773 views

Acid dissociation constant from conductometric data

$\ce{0.007 M}$ aq. solution of anilinium hydrochloride had molar conductivity equal to $\pu{119.4 S cm2 mol-1}$, which became $\pu{103 S cm2 mol-1}$ when a few drops of aniline were added to the ...
Harikrishnan M's user avatar
2 votes
1 answer
160 views

Find cell configuration notation for permanganate in acidic medium

They gave us an unbalanced reaction of permanganate and iodide in acidic medium, and ask to balance the reaction using redox methods and the write the cell configuration notation for the resultant ...
creepshow's user avatar
-3 votes
1 answer
107 views

Which of the following might turn NaNO2 into N2? [closed]

Which of the following might turn $\ce{NaNO2}$ into $\ce{N2}$? A. $\ce{NaCl}$ B. $\ce{NH4Cl}$ C. $\ce{HNO3}$ D. $\ce{H2SO4}$ The answer is B and we have $$\ce{NH4Cl + NaNO2 = NaCl + 2H2O + N2↑}.\tag1$...
youthdoo's user avatar
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1 answer
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What causes ionisation in redox reactions?

I'm trying to understand what's behind the ionisation of atoms in a redox reaction. I apologise if the answer to this question is obvious. I've searched around, but, surprisingly, I haven't found a ...
John O'brien's user avatar
-4 votes
1 answer
279 views

What is the difference between combination reaction and addition reaction [closed]

In my textbook,two definitions were given separately Combination: Two or more substances react to form one product. Addition: Something is added to a chemical substance without elemination. What is ...
Kick's user avatar
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3 votes
1 answer
97 views

Reduction of di-N-substituted imidazole to imidazoline to remove counterion?

I would like to synthesize a di-N-substituted imidazole (compound 4) in its free base form or reduce it to generate an imidazoline (compound 5) to remove the bromide counterion to the imidazole ring. ...
toodles's user avatar
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-1 votes
2 answers
679 views

Why iron reacts with steam to give Fe3O4 not Fe2O3? [duplicate]

Why $\ce{Fe}$ with $\ce{H2O}$ gives $\ce{Fe3O4}$ not $\ce{Fe2O3}$? Like, $\ce{Zn + H2O \rightarrow ZnO + H2}$, why $\ce{Fe}$ doesn't simply gives $\ce{Fe2O3}$ when it reacts with steam?
O M's user avatar
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-2 votes
1 answer
48 views

Where does the ionisation energy for a reaction to take place comes from? [closed]

Can anyone tell me exactly what happens during a chemical reaction in terms of ionisation energy? I know that during a reaction there is an exchange of electrons (except for those where electrons are ...
Zane Stockton's user avatar
-3 votes
1 answer
64 views

Why does metal atom get an effective potential difference in voltaic cells [closed]

Why is it that metal atoms , experience this potential difference when immersed only in their salt solutions. When they are in contact in real life we cannot see current conducting through it.
Naveen V's user avatar
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0 votes
1 answer
76 views

Why does hypophosphorous acid oxidation occur in acidic media?

When one mole of $\ce{H3PO2}$ is treated with excess $\ce{I2}$ in acidic solution, one mole of $\ce{I2}$ is reduced; on making the solution alkaline, a second mole of $\ce{I2}$ is consumed. I am ...
tantan's user avatar
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0 votes
0 answers
637 views

Weight Ratio vs Molar Ratio - Chloramines

I'm working with a delicate experiment whilst trying to test corrosion of stainless-steels in a chloramine environment. I've run into various literature that discusses the formation of different types ...
Kuhrta's user avatar
  • 65
4 votes
1 answer
431 views

Sodium borohydride and lithium aluminium hydride

Both sodium borohydride and lithium aluminium hydride are common reducing agents in organic chemistry. Then can these reducing agents be applied in inorganic chemistry? I mean, for example, reducing ...
Elizabeth's user avatar
0 votes
0 answers
89 views

Formation of hypofluorite from F2 and hydroxide

Why $\ce{FO-}$ can't form in reaction of $\ce{F2}$ with $\ce{OH-}$ but $\ce{ClO-}$ can form on reacting $\ce{Cl2}$ with $\ce{OH-}$? Is $\ce{FO-}$ very unstable? I know that fluorine can't have ...
Harjot Dhillon's user avatar
0 votes
0 answers
100 views

In which medium is Potassium Permanganate a better oxidising agent?

I was in chemistry class just now, and my chemistry teacher gave us three reactions: Reaction 1: $\ce{MnO4^- + e- -> + MnO4^2- (basic medium)}$ Reaction 2: $\ce{MnO4^- + 4H+ + 3e- -> + MnO2 + ...
thundercrypt's user avatar
2 votes
0 answers
142 views

Chloramines & Nitrogen Trichloride vs Stainless Steel [closed]

We've recently experienced excessive corrosion on stainless steel within indoor pool environments. We believe this is due to chloramine (gasses) in the atmosphere. To test this, I plan to create a ...
Kuhrta's user avatar
  • 65
1 vote
1 answer
184 views

Redox titrations : Oxidation of metallic Iron by Potassium Dichromate

$\pu{0.31 g}$ of an alloy of $\ce{Fe + Cu}$ was dissolved in excess of diluted $\ce{H2SO4}$, and the solution was made up to $\pu{100 ml}$. $\pu{20 ml}$ of this solution required $\pu{3 ml}$ of $\frac{...
Ahmad Raza Beg's user avatar
-5 votes
1 answer
107 views

Why is sodium zincate two sodium ions and two oxygen ions but only one zinc ion? [closed]

$2$NaOH + Zn ---> Na2ZnO2+H2 I have always been fascinated by this reaction because it never made sense to me why sodium zincate has such a strange composition. Why does it have two sodium and ...
uggupuggu's user avatar
  • 132
3 votes
1 answer
220 views

Lithium aluminium hydride

Lithium aluminium hydride is an important reducing agent in organic chemistry. Since I cannot find the half-equations telling how this reducing agent performs its action, I am wondering, is lithium a ...
Chemistry is fun's user avatar
0 votes
0 answers
149 views

What is the effect of temperature on titration between Iron(II) sulfate and potassium permanganate

I'm conducting an experiment in school, the titration of Iron(II) sulfate dissolved in H2SO4 against potassium permanganate. In this, I am varying the temperature that the analyte is heated to and ...
Lilith Labans's user avatar
-4 votes
1 answer
61 views

Can this equation be balanced using ion-electron method?

Reaction: $\ce{C2H4 + O2 → CO2 + H2O}$ I want to balance the above reaction using the ion-electron method. My attempt: Ox-half: $\ce{C2^(^-^2^)H4 + 4H2O → 2C^(^+^4^)O2 + 12H^+ +12e^-}$ Red-half: $\ce{...
Ayush Naman's user avatar
-3 votes
1 answer
76 views

Can all equations be balanced using ion-electron method?

Consider the reaction of a mixture of $\ce{C2H4}$ and $\ce{CH4}$ with $\ce{O2}$. Using the hit-and-trial method, this is the balanced chemical reaction: $\ce{C2H4 + CH4 + 5 O2 -> 3 CO2 + 4 H2O}$ ...
Ayush Naman's user avatar
-3 votes
1 answer
83 views

Is it possible for a surplus of electrons to be generated during a chemical reaction? [closed]

I was wondering whether a chemical reaction can produce excess electrons after the completion of the reaction, in addition to generating by-products (chemical compounds) and heat. In other words, can ...
Talha Taki's user avatar
1 vote
2 answers
73 views

Can someone explain why there is OH in the Standard Reduction Potentials Table

$$\ce{SO4^2− + H2O(l) + 2e− <=> SO3^2− + 2OH−}$$ This is the half-reaction that I am having trouble understand. I have read online that OH- is used to cancel out the protons(H+) in basic ...
Metron's user avatar
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1 vote
0 answers
477 views

Why does copper(II) sulfate or iron(III) nitrate work as a catalyst for the iodate variant of the Iodine Clock?

In the iodine clock reaction (iodate variation), the reaction of iodate and bisulfite ions apparently is the rate-determining step. I was wondering if $\ce{Cu^2+}$ and $\ce{Fe^3+}$ will act as ...
Metron's user avatar
  • 37
-4 votes
1 answer
84 views

Why isn't the n factor/valency factor in a disproportionation reaction = twice the number of electrons in a single half reaction? [closed]

I was reading the first answer to Equivalent weight in case of disproportionation reaction there it is said Take a disproportionation reaction:- $\ce{nA -> xB + $(n - x)$C}$ where A is being ...
Saif's user avatar
  • 35
4 votes
1 answer
228 views

How does a silver chloride electrode (Ag/AgCl) convert the potential in aqueous solution to the wire?

I am aware of the redox chemistry that happens at the electrode surface, but I'm not sure how exactly a change in electrical potential in the solution would change the potential in the electrode?
Anthony's user avatar
  • 41
4 votes
1 answer
877 views

What is happening in experiment coating a copper coin with zinc and turning it to brass?

Today in class we did the "gold penny" experiment, where we put metallic zinc and a penny in a zinc chloride $\pu{1 M}$ solution at $\pu{100 °C}$, which caused the penny to turn silver as ...
anonymousaga's user avatar
0 votes
1 answer
106 views

what does the oxidation/reduction potential actually mean? [closed]

The standard potential of a species is actually its tendency to gain/lose electrons and get reduced/oxidized. But what I want to understand : 1- Is the standard potential an absolute quantity, or a ...
Karim mohie's user avatar
2 votes
2 answers
148 views

What are disadvantages of methane or ammonia compared to dihydrogen for metal ore reduction?

Metallurgy, such as steel-making processes, require reducing agents to get rid of the oxygen in metal ores. Using fossil coal for this is a large source of $\ce{CO2}$ globally. Recently, I have read a ...
tobalt's user avatar
  • 129
2 votes
1 answer
117 views

Reduction of La(NO3)3 to La(NO2)3

I'm writing a master's thesis on some lanthanide compounds, in particular those with $\ce{Ce^{+3}}$ and $\ce{La^{+3}}$, although my focus has now shifted to lanthanum, but I ran into a problem when I ...
liuzp's user avatar
  • 142
-1 votes
2 answers
86 views

What is the meaning of "maximum" weight produced after series ot reactions?

$4.14$ grams of a piece of lead was made to react with $\ce{HNO3}$ so as to produce lead nitrate. Lead nitrate further reacts with a series of reagents to form $\ce{(NH4)2PbCl6}$. Then find the ...
Aleph's user avatar
  • 186
5 votes
0 answers
122 views

Regarding the standard reduction potential and electrolyte/solid interface

I am modelling lithium-sulfur batteries ($\ce{LiS}$ batteries) and a strange phenomenom happens during charge, named infinite charging, which I show below: The factor $f_\mathrm{C}$ that appears in ...
Metal Storm's user avatar
  • 3,546
1 vote
1 answer
36 views

EM Induction from Diffusing Ionic Wave Front

I am studying the Belousov-Zhabotinsky Reaction-Diffusion system in ~1mm wide 1-dimensional channels. In my research we are activating the reduced phase with a silver wire and studying the propagation ...
Augustus Thomas's user avatar
-4 votes
1 answer
55 views

What are some efficient approaches for balancing long chemical equations? [closed]

I am having some difficulties in balancing chemical equations involving many elements. It takes a lot of time (for me) to balance the coefficients using the hit and trial method. Especially like this ...
Golden_Hawk's user avatar
-3 votes
1 answer
189 views

Why does increasing the surface area of the cathode submerged in the electrolyte increase the current in a galvanic cell? [duplicate]

I can understand why increasing the surface area of the anode would increase the current, because the rate of oxidation will be increased resulting in a greater rate of flow of electrons through the ...
averdago's user avatar
1 vote
1 answer
87 views

Why can sulfate be oxidized to peroxodisulfate?

I am currently in high school and have encountered the following reaction in my course on electrochemistry: $$\ce{2 SO4- -> S2O8^2- + 2 e-}$$ Why this reaction happens in the first place? Isn’t the ...
TheCuriousOne's user avatar
5 votes
3 answers
917 views

Must a strong reducing agent be a weak oxidising agent, and vice versa?

As titled, must a strong reducing agent be a weak oxidising agent, and must a strong oxidising agent be a weak reducing agent? For instance, fluorine is a very strong oxidising agent, and it cannot ...
Jelly Qwerty's user avatar
4 votes
2 answers
645 views

Positive and negative voltage readings of chemical cells

In the experiment of chemical cells, I connected a magnesium electrode , a copper electrode and a multimeter in a complete circuit. When magnesium electrode is connected to the negative terminal and ...
Freeby Freeby's user avatar
0 votes
1 answer
483 views

How does sodium react with methanol?

Strong acids of $\ce{AH}$ type readily dissociate to its constituent ions (considering the solvent is water): $\ce{A-}$ and $\ce{H+}$. But the mechanism of the reaction between sodium metal and ...
Chesx's user avatar
  • 140
1 vote
0 answers
106 views

Why doesn't copper react with nitrate salts?

Copper reacts with nitric acid according to this equation: $$\ce{Cu + 4 HNO3 -> Cu(NO3)2 + 2 NO2 + 2 H2O}$$ This is a redox reaction with copper getting oxidized, and nitrogen getting reduced. ...
JLB's user avatar
  • 49
1 vote
2 answers
401 views

When HI reacts with H2SO4, why is the sulphate ion reduced to hydrogen sulphide instead of sulfur dioxide?

When $\ce{HI}$ reacts with $\ce{H2SO4}$, it can be represented by the following chemical equation: $$\ce{8HI + H2SO4 -> 4I2 + H2S + 4H2O}$$ However, when $\ce{HBr}$ reacts with $\ce{H2SO4}$, the ...
Jelly Qwerty's user avatar
2 votes
0 answers
59 views

Question about reaction in battery

I made a battery like this. $\ce{(-)Al|HCl,CuSO4|Cu(+)}$ By piling up 6 battery of this(actually I made this using 10 yen and 1 yen coins:10yen coin is Cu and 1 yen coin is Al.) I could turn on an LED ...
satoru kurita's user avatar
-1 votes
1 answer
250 views

Decomposition of ammonium nitrate

Consider the decomposition of $\ce{NH4NO3 -> N2O +2 H2O}$ How do I show this is a redox reaction. Within the $\ce{H2O}$ the oxidation state of $\ce{O}$ is $-2$ and the oxidation state of $\ce{H}$ ...
Stark's user avatar
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