Reduction-oxidation reactions: all chemical reactions in which atoms have their oxidation state changed.

learn more… | top users | synonyms

0
votes
1answer
28 views

How to identify a substance acting as an acid

For question ii, it asks to state a reaction showing $\ce{H2SO4}$ acid acting as an acid. What does it mean acting as an acid? Donating a proton? Very confused as to what to look for. The answer ...
1
vote
0answers
26 views

Vycor + hydrogen at 750°C - reduction?

Does anybody have experience with Vycor 96% silica tubing in hydrogen at bright red heat, around 750°C, regarding its reduction to silicon monoxide or elemental silicon?
1
vote
1answer
35 views

Titration of ferrous oxalate with potassium permanganate

Number of moles of $\ce{MnO_4^-}$ required to oxidize one mole of ferrous oxalate completely in acid medium will be: (a) 7.5 moles (b) 0.2 moles (c) 0.6 moles (d) 0.4 moles In ...
0
votes
1answer
39 views

Balancing Redox Reaction [closed]

$\ce{a\cdot Zn + b\cdot NO3^- + c\cdot OH- -> d\cdot Zn(OH)4^{2-} + e\cdot NH3}$ The fact that there already is an $\ce{OH-}$ in the reaction confuses me. It should also be noted that the last ...
5
votes
1answer
48 views

What is the oxidizing agent for Fe in the following redox reaction?

Redox: $\ce{Fe + 2HCl -> FeCl2 + H2}$ Oxidation: $\ce{Fe -> Fe^{2+} + 2e-}$ Reduction: $\ce{2H+ + 2e- -> H2}$ The $\ce{HCl}$ and $\ce{H2}$ are formed by covalent bonds. The $\ce{FeCl2}$ ...
1
vote
1answer
57 views

Which two substances react spontaneously?

Which two substances react spontaneously? (A) $\ce{Ag}$ and $\ce{Cu}$ (B) $\ce{Ag+}$ and $\ce{Cu}$ (C) $\ce{Ag}$ and $\ce{Cu^2+}$ (D) $\ce{Ag+}$ and $\ce{Cu^2+}$ ...
5
votes
1answer
115 views

Why does HNO3 not give off H2 when reacting with Cu?

A dilute solution of which acid is most likely to produce a reduction product other than $\ce{H_{2}}$ when it reacts with a metal? (A) $\ce{HF}$ (B) $\ce{HCl}$ (C) $\ce{HNO3} $ ...
1
vote
1answer
299 views

Redox reaction with H2O2+KI+H2SO4 ->?

I've managed to write down the correct reaction (I think): $\ce{H2O2 + KI + H2SO4 -> K2SO4 + I2 + H2O}$ Now I need to balance this using the Ion-Electron method in an acidic environment. Normally ...
2
votes
3answers
82 views

Can oxygen burn in hydrogen

Most combustion happens involves the fuels burning in an oxidant. But there seems to be no reason that it cannot happen in the opposite way. Are there any experiments on oxygen burning in hydrogen? Or ...
2
votes
2answers
153 views

For the redox reaction, HCl + SnCl2 + KMnO4 , what are the products?

In the redox reaction, where HCl is the excess reactant do these reactions produce following half rxns? half: $$\ce{SnCl2 -> Sn^{4+} + 2e-}$$ & $$\ce{8H+ + KMnO4 + 5e- -> Mn^{2+} + ...
1
vote
2answers
57 views

what are reduction oxidation reactions?

in the picture, the product is a neutral material, but in the illustration of the molecular structure, the compound is shown in its ions, why we can't show it in its ions even in the equation or if ...
2
votes
1answer
113 views

How does iron rust in basic conditions?

I performed an experiment about the corrosion of iron. I used acid and base in the experiment. I understand that the acid speeds up the corrosion of iron. But I don't understand why the base also ...
8
votes
3answers
108 views

Would it be possible to produce a non-toxic atmosphere using a coal fire and frozen oxygen?

A Pail of Air is a classic science fiction short story by Fritz Leiber from 1951 describing how a family survives on an Earth that has left its orbit around the sun, using desparate low-tech methods: ...
2
votes
2answers
88 views

Why can we disregard stoichiometric coefficients when computing reduction potentials?

Example: A $Cd // Cr$ Galvanic cell has redox half reactions: $\ce{Cd^{2+} + 2e^- -> Cd}$ $E_{cell}$ = -0.4 $\ce{Cr^{3+} + 3e- -> Cr}$ $E_{cell}$ = -0.7 Balanced equation of reaction ...
0
votes
2answers
107 views

Can bromide ion reduce ferric ion?

Can bromide ion reduce ferric ion ? Just a query. In my opinion it can since bromide ion can undergo oxidation. Is my answer correct?
3
votes
0answers
76 views

How does the ambient temperature affect the rate of redox reactions in a salt lake?

Many years ago, I used to work as a gold exploration geologist. One of the main locations was a salt lake in Western Australia detailed in the document WMC Resources Exploration Successes inN Lake ...
4
votes
0answers
68 views

How can normal potentials be explained?

For example (for reductions) $$ \ce{2e-} + \ce{Cd^{2+}} \rightarrow \ce{Cd}:\mbox{ } E^0 = -0.403 V\\ \ce{2e-} + \ce{Ni^{2+}} \rightarrow \ce{Ni}:\mbox{ } E^0 = -0.25 V $$ How can I rationalize this ...
3
votes
3answers
110 views

Explaining redox reactions to a 6 year old?

In a similar vein and for pretty much the same reason as I post this question on the Physics.SE site, what would be a an effective means to promote understanding about redox reactions to a 6 year old? ...
0
votes
1answer
32 views

Electrolysis Anode equation

In the electrolysis of $\ce{Na2SO4}$, is it valid to write the anode half-reaction (oxidation) as $$ \ce{OH-} \rightarrow \ce{H+} + \frac{1}{2}\ce{O2} + 2\ce{e-} $$? My book says it's $$ \ce{H2O} ...
3
votes
1answer
43 views

Are these two reactions equivalent?

I'm supposed to balance a redox equation. I arrive at $$ \ce{H2O} + \ce{NH4+} + 2\ce{S^{2-}} + \ce{O2} \rightarrow \ce{NH3} + 2\ce{S} + 3\ce{OH-} $$ The "official" solution is $$ 4 \ce{NH4+} + ...
7
votes
2answers
93 views

Can a battery powered by iron and air really provide a feasible power source for automobiles?

I'm referring to the Shuttle Battery recently announced (read more on it here) that suggests that: The energy density of the device is up to 7,700 Wh/L. It is more than 5 times higher than ...
1
vote
1answer
89 views

Is it true that iron (Fe 0+) cannot exist when there's water around?

So somebody told me that iron metal (zero charge) cannot exist at all when $\ce{H2O}$ is present because it will all turn into rust. How is this possible? Isn't there some sort of equilibrium? Does it ...
0
votes
0answers
87 views

Why is CuSO4 used as electrolyte while purifying copper?

During the electrolytic purification of copper, the electrolyte is taken as copper(II) sulphate ($\ce{CuSO_4}$). Is there any particular reason for this? Could another salt of copper, say ...
0
votes
1answer
75 views

Why are more easily oxidized elements more reactive than less easily oxidized elements?

Why do the more easily oxidized elements displace the less easily oxidized elements? Question inspired by Activity Series of Metals
0
votes
2answers
1k views

Help in balancing the redox reaction: Mg + HNO3 -> Mg(NO3)2 + N2O + H2O

I just have this redox reaction that i can't balance using half reaction method. it goes like $\ce{Mg + HNO3 -> Mg(NO3)2 + N2O + H2O}$ What i get at the end is $\ce{2Mg + 6HNO3 -> ...
2
votes
1answer
371 views

Vertical lines in a Pourbaix Diagram

I know that because of the absence of the hydrogen ions in a reaction ($n_{H+} = 0 $) , the correspondent E-ph line have to be horizental , but what exactly the types of reactions (if there is) that ...
3
votes
1answer
497 views

Electrolysis of Aqueous copper (II) nitrate

$\ce{Cu(NO3)2_{(aq)}}$ There are two copper blocks sitting in the solution, a battery is attached onto both of them, providing enough energy to start the reaction. Since solid pieces of copper are ...
1
vote
1answer
437 views

Balancing redox reaction with one reactant

Consider the following acidic reaction: $\ce{As -> H2AsO4- + AsH3}$ How would I go about balancing this using the half reaction/ion-electron method?
2
votes
1answer
270 views

Bayer-Villiger Reaction - Migratory Aptitude

In short, I do not understand how or why the migratory aptitude is as listed in every textbook I've read. Firstly, they talk about a positive charge being built up that is stabilised by the movement ...
3
votes
1answer
118 views

Which reaction between Lugol and Hydrogen peroxide?

The Lugol solution is a mixture of $(K^+ , I^- )$ and $I_2$ such that $I_{3}^-$ are formed by: $I^- + I_2 \rightarrow I_{3}^{-}$ I know that the brown color comes from $I_2$, but in this solution ...
1
vote
2answers
47 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? ...
4
votes
1answer
169 views

Prediction of ionic reduction?

Here are some standard electrode potentials:- $$SO_4^{2-} + 4H^+ +2e^-\rightarrow SO_2 +2H_2O\\E^o=0.17V\\ NO_3^-+4H^++3e^-\rightarrow NO+2H_2O\\E^o=0.97V\\ NO_3^-+2H^++e^-\rightarrow ...
3
votes
1answer
1k views

What's the technical term for supercharging an acid with an oxidizer? And does it always work?

In a recent Mythbusters episode, where they tested some Breaking Bad chemistry assertions, they debunked the hydrofluoric acid body-dissolving myth referenced elsewhere in Chemistry.SE in the question ...
5
votes
1answer
247 views

What is the net ionic equation for this molecular equation?

I have this problem, Liquid bromine is added to a container of sodium iodide crystals I interpreted it with this molecular formula $\ce{Br_{2(l)} + 2NaI_{(s)} \rightarrow 2NaBr_{(s)} + I_{2(g)}}$. ...
2
votes
0answers
29 views

Shift of the null half-reaction potential

If we change the null half-potential, would it change half-potentials of other half-cell reactions by the same amount, so that voltages of net reactions stay the same?
0
votes
0answers
40 views

Finding one of the two unknown potentials with a given voltage of a net reaction

A half-cell consisting of palladium rod dipping into a $1\ M$ $Pd(NO_3)_2$ solution is connected with a standard hydrogen half-cell. The cell voltage is $0.99\ volt$ and the platinum electrode in the ...
1
vote
1answer
338 views

Balancing the equation when $\ce{MnO2}$ is reduced to $\ce{MnO}$ by $\ce{H2(g)}$

I am studying for a final tomorrow and I was going through some problems on older exams and came across one which I wasn't really sure how to solve. The problem is to write the balance equation when: ...
1
vote
1answer
67 views

Electrode potentials at interfaces?

My questions relates to the fundamental concept of electrochemistry, more specifically the electrode potentials. 1) First, why is there a potential difference at the interface of two phases? ...
0
votes
1answer
65 views

Oxidation number and Pourbaix diagrams

In a Pourbaix diagram (E-ph diagram) where the regions are given , but the assignment of these to the elements we have is not done yet , how can the oxidation numbers helps me out assigning each ...
3
votes
1answer
60 views

Reaction of an electrode

Why is the cathodic reaction of $I^-/AgI/Ag$ is $$\ce{AgI + e- -> Ag + I-}$$ but not, $$\ce{Ag+ + e- -> Ag }$$ whereas, in $Ag/AgCl(s)$, $KCl$(0.2M); it is $$\ce{Ag+ + e- -> Ag}$$
1
vote
0answers
29 views

Will JB Weld break down with the use of R-410a refrigerant

What I am trying to verify is that if I use JB Weld as a solution to a cracked fitting, will it hold up both under the pressures and temperatures of R-410a refrigerant. Normal operating pressures are ...
4
votes
1answer
178 views

Why does sodium react with water?

The reaction of sodium with water is quite infamous. $\ce{2Na + 2H_2O \rightarrow 2NaOH + H_2}$ But exactly why does $\ce{Na}$ displace $\ce H$ in $\ce{H_2O}$?
0
votes
1answer
76 views

The difference in the maximum and mimimum oxidation state of $\ce{S}$ in $\ce{(S4O6)2-}$ [closed]

Find the difference in the maximum and mimimum oxidation state of S in $\ce{S4O6^{-2}}$. My answer is 2 but the answer given is 5. Could you help?
0
votes
0answers
31 views

What are the factors affecting disulphide bond formation/maintenance/scission?

For example, how does pH affect strength and rate of bond development? Thank you in advance for any input offered.
0
votes
2answers
207 views

What is this brown liquid that I got when I boiled glycerol and water solution?

I boiled a solution of glycerol and water at about 160 degree Celsius and got a brown liquid much less in volume (boiled off the entire water I think; also not so sure about the accurate temperature). ...
3
votes
4answers
12k views

Why is it important to use a salt bridge in a voltaic cell? can a wire be used?

I was learning about voltaic cells and came across salt bridges. If the purpose of salt bridge is only to move electrons from electrolyte solution to the other, then why can I not use a wire? Also, ...
2
votes
2answers
331 views

Are fractional oxidation states possible?

To get the oxidation number of the carbon in the $\mathrm{C_8H_{18}}$ I should do: $$ -\frac{18}{8}=-2.25 $$ right? But in that way, I get an oxidation number with a comma, is that normal?
3
votes
2answers
246 views

Cathodic protection of aluminium

I am planning an experiment for a chemistry class about corrosion. I am going to show how different prevention methods affects the corrosion of iron and aluminium parts using bleach as the oxidizer. ...
2
votes
1answer
478 views

Identifying Reaction Types

I need help on identifying precipitation, acid-base, and redox reactions. I know what each one is in theory: Precipitation: Creating a solid Acid-Base: neutralization Redox: exchange of electrons ...