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

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Why would electrode reaction in galvanic cell stop when there's no neutrality in each cell?

I know that the salt bridge produces ions to balance out the positive and negative ions in each solution, but why won't it work without a salt bride? Would it even work at the start since there's few ...
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Question on notation of redox reactions

I've got a question regarding 'notation' for redox reactions. Suppose you are asked to identify the oxidizing and reducing agents for a simple reaction like this one: $$\ce{Cl2(aq)}+\ce{2KI(aq)} ...
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How to identify a redox reaction and how to assign oxidation numbers [closed]

Indicate whether the balanced equations involve redox equations. Identify the elements that undergo changes in oxidation number. $\ce{I2O5(s) + 5CO(g) -> I2(s) + 5CO2(g)}$ ...
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Is there non-redox reaction?

Redox reaction is a type of chemical reactions, and the result of electron transfer. But all chemical reactions are somehow involved electron transfer! Are there chemical reactions without electron ...
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Use The Half Reaction Method to Balance the Following Equation in Acidic Solution [closed]

$\ce{Fe^2+ + MnO4- -> Fe^3+ + Mn^2+}$ What steps should I take?
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Nernst equation and electrolysis

Let's say we have a stable solution of $\mathrm{A}_{\left(\mathrm{aq}\right)}^{2+}$ and $\mathrm{C}_{\left(\mathrm{aq}\right)}^{+}$ , with their respective counter-ions. The associated redox ...
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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: $\ce{3Cu + 2NO3- + 8H+ <=> 3Cu^2+ + 2NO + 4H2O}$ ${E = 0.62V}$ $\ce{3Cu + 2NO3- + 4H+ <=> 3Cu^2+ + 2NO2 + 2H2O}$ ${E = 0.45V}$ The Nernst equation tells us ...
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What exactly is net ionic equation?

I once saw a problem, iron ions(II) titrated with potassium dichromate to produce Fe(II) and Cr(III). If I am to write the net ionic equation of this reaction, I got to make potassium dichromate on ...
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In this simple redox reaction, why does the Hydrogen oxidize the calcium metal?

I am understanding that the Hydrogen ions oxidize the calcium metal, neutralizing itself and creating a calcium cation. My question is why does the Hydrogen oxidize the calcium? Doesn't it prefer to ...
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Redox reactions - alkene to alcohol

How is the "correct" answer not a redox reaction? Isn't the "correct" choice a textbook example of an organic redox reaction? After all, we are breaking a C-C bond and replacing that with a C-O ...
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Standard electrode potential for electrolytic vs galvanic cells

Whys is the standard electrode potential (-) for electrolytic cells but positive for (+) galvanic cells. If E°cell > 0, then the process is spontaneous (galvanic cell) If E°cell < 0, then ...
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How does salt and water help corrosion?

I was always wondering why iron only rusts when it gets wet. I know that for example aluminium oxidises on its own on regular basis. I also heard many complains that salt used to remove snow from ...
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Balancing the redox reaction

Question: Balance the following redox reaction: $$\ce{FeS2 + O2 -> Fe2O3 + SO2}$$ My Efforts: I tried balancing with oxidation number method. First of all i determined the oxidation ...
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Why does a chemical have more than one oxidation number?

Like for group I metals, it is understood that all the elements in the group would have an oxidation number of +1. As far as I know, oxidation number is how much electron the element loses/gains. ...
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Why does potential chemical energy decrease with increasing oxidation of carbon?

I saw an interesting spectrum in my biology class the other day. On the left end was methane - the least oxidized form of carbon - and the most energetic form of carbon (at least relative to what else ...
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Electron Transfer in Organic Reactions: Why Does Brown Iron Oxide Improve Burn Rate of Rocket Candy?

On wikipedia, this statement exists about rocket propellant aditives: Metal oxides have been found to increase the burn rate of sugar propellants. [...] Most often used are iron oxides. Red iron ...
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Sodium metal reduction of chloroform

In discussing how best to deuterate chloroform, it occurred to me that we could use sodium metal to reduce hydrogen into hydrogen gas. If this could actually happen, this would be a great thing - we ...
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What are the other definitions of redox reactions besides the gain or donation of oxygen?

As my teacher told us, oxidation is the gaining of oxygen and reduction is the donation of oxygen. In my reference book there are other definitions of this reaction. So please give me some alternate ...
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Potassium Atom can act as reducing agent, yet ion cannot?

I am currently looking through a revision sheet, however it has caught me on a question 'Explain why a potassium atom can act as a reducing agent yet a potassium ion cannot'. I have done brief ...
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pH Changes in primary cells

Primary Cells - pH changes during discharge Alkaline Cell: Manganese Dioxide Zinc Alkaline Cell Anode (-) $\ce {Zn(s) + 2OH^{−}(aq) → ZnO(s) + H2O(l) + ...
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Fuel Cell Chart - Anode, Cathode, Electrolyte

Can someone please check my table to make sure I have the correct information. I am especially unsure of the parts highlighted in yellow:
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Why are imines more susceptible to reduction than carbonyl compounds?

Why are imines more susceptible to reduction than carbonyl compounds? Imines react with $\ce{NaCNBH3}$ while the carbonyls don't.
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Determining redox half-reactions of single displacement reactions

For the following double displacement half reaction, the half reactions can be determined easily using the oxidation numbers. $$\ce{MnO_{4(aq)}^{-} + IO_{3(aq)}^- -> MnO_{2(s)} + IO_{4(aq)}^-}$$ We ...
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How to get sodium from sodium aluminate?

The sodium aluminate is formed when aluminium or aluminium hydroxide reacts with water solution of lye. After drying the water you'll end up with white crystals - sodium aluminate. I was wondering if ...
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Why are metal oxides generally more stable than their corresponding elemental forms?

Why is the oxidation of certain metals such as iron favorable from a thermodynamic standpoint? What is it about these metal oxides that makes them inherently more thermodynamically stable than their ...
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Nitrobenzene reduction with (tin) Sn catalyst: Why is C-H bond cleavage preferred over O-H bond cleavage?

I am trying to understand this mechanism for nitrobenzene reduction with $\ce{Sn/HCl}$. I do not understand why it implies that you pull off the $\ce{C-H}$ hydrogen instead of the $\ce{O-H}$ hydrogen ...
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What factor determines the strength of reducing agents 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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HI/P reduction mechanism

I recently answered a question about Breaking Bad's initial methamphetamine production method (i.e. the reduction of (pseudo)ephedrine). The reaction is as follows: (Source: ...
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Writing Half-Reaction for Iron-Hydroxide Oxidation Reaction

Here is the unbalanced equation.$$Fe(OH)_{2(s)}+O_{2(g)}\rightarrow Fe(OH)_{3(s)}$$Therefore, one half reaction is $$Fe(OH)_{2(s)}+O_{2(g)}\rightarrow Fe(OH)_{(3s)}$$ and the other half reaction is ...
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Why is formic acid considered an acid if it is a reducing agent?

My understanding was that since the acceptance of Lavoisier's revised Easter Memoir of 1778, all acids were understood to be oxidising agents.* However, formic acid is often listed as a reducing ...
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Why is chloride oxidised instead of water in copper chloride electrolysis?

For the Electrolysis of Copper Chloride: Cathode: $\ce{Cu^{2+} + 2e- <=> Cu}$ Anode: $\ce{2Cl <=> Cl2 + 2e- }$ I am confused about the reaction taking place at the anode. Wouldn't ...
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Oxide Anions in Redox

Consider the following unbalanced redox equation: $\ce{NO_2^- +e^- -> NO3^-}$ This occurs in acidic media. My professor would note that an negative two oxidation state oxygen "disappears" from ...
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In a mixture of ammonia and hydrogen hypochlorite, how do I determine the oxidising and reducing agent?

$$\ce{NH_3 + HOCl <=> NH_2Cl + H_2O}$$ How do I figure out what the oxidizing agent is and reducing agent? I know that the oxidizing state of $N$ in $\ce{NH_3}$ is $-3$, but I'm not sure how to ...
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Why does blood get further oxidized than Iron oxide?

Oxygenated blood is bright red and deoxygenated blood is dark red or brown. If you take oxygenated blood and leave it in the air it will turn dark red, then brown, then finally a bluish green from ...
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Elemental Potassium as both an oxidizer and a reducer

On this table I realized that elemental potassium could adopt oxidation states of -1, 0, and +1. http://en.wikipedia.org/wiki/List_of_oxidation_states_of_the_elements Does this mean that elemental ...
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Average Oxidation State - Utility?

What is the purpose of calculating an average oxidation state for a certain element in a compound? Hence the “average oxidation state” of carbon in acetic acid is 0. And the oxidation state ...
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Hydrogen Peroxide as an Oxidizer

Why is HOOH such a good oxidizer? I understand that the oxygens in HOOH are in a negative 1 oxidation state, and that oxygen generally adopts an oxidation state of negative 2. I also know that ...
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Corrosion of metals and observations in the agar medium?

I want to know which metals oxidize and which is reduced and changes in medium and observations? According to my knowledge more corrosion will take place in Zn and Fe also corrode. Then copper ...
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What makes sulfur-containing compounds such good antioxidants?

Many sulfur-containing compounds (like glutathione and cysteine groups) have high antioxidant activity. Why?
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Reaction mechanism of combustion of H2?

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 $\ce{H}_2$ was. I only study (well almost) organic ...
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How do I find out if ions are oxidised/ reduced based on half cell potentials?

I have a question that I keep getting wrong and I need some help on it. Assuming standard conditions, answer the following questions. (yes/no) Is $\ce{Fe^{2+}(aq)}$ capable of reducing ...
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can sodium persulfate etch or damage a titanium heater?

I use Sodium Persulfate to etch copper on a PCB process. I have been using glass heater on the etching tank but the glass is too fragile; it breaks too easily. I read that titanium heater is used ...
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On spontaneity of a redox reaction

Suppose we have a redox reaction and we want to see in what direction the reaction is spontaneous. We do this by comparing the standard reduction potentials of the sub-reactions available in the main ...
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What do the half-reactions need to be for balancing a redox reaction in an acidic medium?

Question: Balance the following reaction: $\ce{CuS + SO4^{2-} -> CuO + SO2}$ My Efforts: Number mentioned in the brackets oxidation number of S I have found out that the oxidation ...
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Why is coating with an oxide considered oxidation

I looked up the word oxidize and one of the definitions is to make it an oxide which is what happens when iron gets rusty(even though there is also iron hydroxide in rust). Another was to coat with ...
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Finding the Oxidation number

I have got the homework to balance the following redox reaction. $\ce{Cr(OH)3- + HO2- -> Cr2O7^{-2} + OH- }$(Basic medium) To balance this reaction first thing we need to do is to find the ...
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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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Any possible additives to a drain cleaner I use as a source of NaOH?

It is in pellets. And the box says main ingredient $\ce{NaOH}$ at least $30\%$ (I hope it's more). The box also says "aluminium catalyst". My goal was to take these pellets and dissolve them in water ...
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Reduction and Oxidation - Alternate definitions

Why is reduction defined as the gain of hydrogen? Is it because hydrogen has a very low electronegativity and easily donates its electrons to other elements? From what I understand reduction is ...
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Redox properties of methyl radical

The methyl radical, $\ce{.CH3}$, is a strong oxidant and a strong reductant according to Wikipedia. Why is this so? Any additional reasons to the ones below? I know that an oxidant itself is ...