Talk:Redox

Needs etymological explanation

Would someone please add a section clarifying the usage "oxidation" (which obviously does not mean "adding oxygen") and "reduction" (what exactly is reduced?). Thanks. Tmangray 00:14, 1 February 2007 (UTC)

I agree entirely, in its current form this article is quite obfuscatory rather than explanatory, and well below Wikipedia's normal level of clarity. Please could someone rewrite it with the end user in mind. Thanks :)

Er, the following statements from the introductory section:

• Oxidation describes the loss of electrons by a molecule, atom or ion
• Reduction describes the gain of electrons by a molecule, atom or ion

seem quite clear and unobfuscated as a description of these terms. And a bit later in that section, we get a more proper definition:

Thus, oxidation is better defined as an increase in oxidation number, and reduction as a decrease in oxidation number.

Are those close to being clear, and a small wording-change could fix the whole problem? Or are those hopelessly confusing and we need to start over? DMacks 16:13, 20 February 2007 (UTC)

I'm still a litte confused, it seems like the simple definition and the detailed definition contradicts themselves? More incisively speaking, the simple definition states (in a nut shell) that oxidation is the loss of electrons and that redution is the gain of electrons...While the detailed description basically states the opposite of the two in that oxidation is to gain as reduction is to loss (which in turn contradicts the simple definition)...Am I making any sence? -Thanks Gunnar Berlin 21:09, 26 February 2007 (UTC)

Ahah! Remember that the electrons, the "things" that are being gained or lost, are negatively charged. So gaining negatively-charged things causes a lower charge. More electrons == lower oxidation state. DMacks 21:17, 26 February 2007 (UTC)

Thank you that definatly clears it up for me now--Gunnar Berlin 21:36, 26 February 2007 (UTC)

Query

what are the reaction between a solution containing hydrated ethanedioic acid with sodium enthanedioate and hydroxyl ions?

Generally speaking, it is advised you use more well known and less cryptic names, namely oxalic acid and sodium oxalate. Also, unless you mean a free radical, they're called hydroxide ions. I'm guessing that oxalic acid is reacting with sodium hydroxide to make sodium oxalate, I can't see any other possible reaction. Kr5t 02:21, 29 March 2006 (UTC)

Id just like to know where the section on using redox reactions as a starting point to balance complicated chemical equations is. It seems that that was kind of an important thing to leave out. In case anyone doesn't know what I'm talking about, it uses the precept that charge, like energy, must be balanced in a chemical reaction. For example:

$CH_{3}OH+O_{2}->CO_{2}+H_{2}O$

This isn't easy to balance on first look, but by finding the oxidation charges in the redox reaction, it can give you a start.

$C^{-2}H_{3}^{+1}O^{-2}H^{+1}->C^{+4}O_{2}^{-2}+H_{2}^{+1}O^{-2}$

ΔC = 6 ΔO = 2 As you can see, the charge difference is not equal, but it could be made equal by multiplying the ΔO by 3. So try this in the eq (remember ΔO is the atomic, not the moleculer ratio)

$CH_{3}OH+3/2O_{2}->CO_{2}+H_{2}O$

Get rid of the fraction:

$2CH_{3}OH+3O_{2}->2CO_{2}+2H_{2}O$

Spot check the last balance:

$2CH_{3}OH+3O_{2}->2CO_{2}+4H_{2}O$

Sorry for the complicated example, but its a good one.

Merge

Oxidation should be merged into this article!!! Reduction (chemistry) redirects to Oxidation. See Talk:Oxidation#Merge?.

210.50.105.135 12:17, 5 Nov 2004 (UTC)

Oxidation has been merged into this article.

Brianjd 06:43, 2004 Nov 7 (UTC)

Add titration to this article!

I think this subject article would be better if the topic titration is added to it.

Why? What does titration have to do with redox? 208.193.132.253

Haha, not only are these totally different topics, acid/base reactions (transfer of H+ protons) are almost the exact OPPOSITE of redox reactions (transfer of e- electrons), so it's a humorous question, chemistry-wise. Jhum101 10:38, 7 March 2006 (UTC)

As a matter of fact, I always thought scientists in general ought merge the definitions. An acid base reaction can be transfer of proton, H+, Arrhenius definition and later refined Bronsted-Lowry, transfer of a pair of electrons, Lewis definition, or transfer of O_2- ion, which I don't think has been named, but does occur:

CaO + CO₂ -> CaCO₃

wherein what really happens is O^2- + CO₂ -> CO₃^2-

Also, Lewis definition defines it as bond making/breaking, also part of redox definition. Indeed, the Acid-Base Reaction Theories Page says that Usanovich tried defining it as transfer of negative positive charges or making/breaking bonds, exactly, pretty much, the definition of redox. It says scientists did not like Usanovich's definition because it overlapped with redox--step back and take a look, guys, they really not only overlap, they're the same.

EVEN ASSUMING EVERYTHING I JUST SAID WAS JUNK, there are as a matter of fact redox titrations. In fact, I did an experiment where I was trying to find the solubility product constant of calcium iodate, and the way I was doing this was by titrating the iodate ions in a saturated solution of calcium iodate with hypo, or sodium thiosulfate. The reaction between them

IO₃^- + 6S₂O₃^{2- + 6H+ -> I- + 3S₄O₆2- + 3H₂O}

is obviously redox.

Kr5t 02:13, 29 March 2006 (UTC)

There are many titrations that have nothing to do with redox; there are many redox reactions that have nothing to do with titration. Just because there are some examples of overlap doesn't mean the topics are the same (or even substantially related in principles) and even if there were substantial overlap of the subjects, it's okay to have related topics on different pages if there is a lot of material to cover on each. OTOH, if someone wanted to note on the redox and titration pages that some titrations use redox reactions and link between the pages, well that's certainly okay IMO. DMacks 04:59, 12 April 2006 (UTC)

My point is that there is titration in both and titration shouldn't be excluded from the redox page unless it is excluded from the acid-base reactions page as well. Point being that titration is equally important in both, so if there is any good reason to exclude or include titration in one page, it should be equally applicable to the other page. Acid-base: How strong an acid is acetic acid in vinegar? Go titrate it. Redox: How strong an oxidizing agent is hypochloric acid in bleach? Go titrate it. Kr5t 03:03, 19 April 2006 (UTC)

Right. I think we (at least Kr5t and I) are in violent at-least-semi-agreement here. As I said, I'm not opposed to including redox titrations here on the redox page. Or should we just mention that one can do a redox titration and then link to the Redox titration page (which could then be improved beyond its current stubbiness)? DMacks 04:19, 19 April 2006 (UTC)

It's not altogether too stubby right now. However, I think that's a lousy example. A simple one, like titration of laundry bleach, would be a whole lot better. Violent semi-agreement? Thats kindofa oxymoron...unless I don't understand what you're saying...which I don't...but anyhow, we do agree. Kr5t 21:03, 3 May 2006 (UTC)

Standardized Nomenclature

Chemical reactions should be denoted by "=", not by "→". The latter implies a net forward reaction, while the former implies a stoichiometric equation or an equilibrium (IUPAC,Italic text Quantities, Units and Symbols in Physical ChemistryItalic text, 2005).

This nomenclature emphasizes the thermodynamic reversibility of the reaction, the associated equilibrium constant, and (in the case of redox reactions) the associated redox potential.

Thus A + B = C + D implies K = exp(-ΔG/RT).

Btarski 18:26, 28 January 2006 (UTC)

Usually you are interested in a chemical reaction because you want to make something that you don't have out of something else that you do have. It's true that some equations are equilibrium in the plain sense (equilibrium constant is not on the order of 10^40), in which case you denote them by a double arrow, but many reactions, such as corrosion, fire, combustion, or most chemical laboratory executable reactions do get driven in one particular direction, because your equilibrium K is huge, in which case using the arrow should be fine, you're denoting your intent, what you're attempting to make, there should be nothing wrong with conveying that extra information in your equation. Anyone with a proper chemistry education will know that every reaction is always an equilibrium reaction. For instance, magnesium will react with silicon dioxide to form magnesium oxide and silicon, but in the Pidgeon Process it's the other way around. The arrow you use denotes your intent, which way you're driving the reaction, whether towards making magnesium metal from silicon and magnesium oxide, or making silicon out of magnesium and silicon dioxide. Sillybilly 03:26, 29 January 2006 (UTC)

Agreed. I just glanced over to my open O-chem textbook, and one-way arrows are used for almost every reaction. Equal signs are never used, and if the equilibrium is important, the double arrow symbol, "⇌", is used. Jhum101 10:45, 7 March 2006 (UTC)

If you want to standardize it, going for a nonstandard standard isn't the best way to go about it ;)(heh). Chemical reactions have never used the equal sign and probably never will. When a reaction has an extremely high K value, orequilibrium constant, a singlle arrow is used, otherwise a double arrow is used (not included in normal fonts so I won't try to show it). Note--don't confuse equilibrium constant K with rate constant k. It's case dependant, so if k is large but K isn't (not very likely), it means that although it reaches equilibrium really fast, theres still more reactants than products present in the equilibrium mixture. Kr5t 19:47, 2 April 2006 (UTC)

Oxidation State Notation

I agree with the points about chemical reactions, they should definitely use arrows. However, I also think that when giving examples of redox reactions, we should use the standardized notation of putting the charge after the number for ions only. For example, when talking about oxidation states, using -2 for O makes more sense than 2-, since 2- denotes that oxygen is an ion. However, sometimes (especially in double replacement reactions) an ionic compound can be broken up and and reformed into covalent compounds. Since charge different must always be equal, one must still look at the charges of the elements, so you should use -2 in all cases just in case there are no ions (e.g. 2H⁰₂ + O⁰₂ -> 2H⁺¹₂O^-2) -Mirag3 21:36, 6 October 2006 (UTC)

Half-Reaction Method

The half-reaction method for balancing redox reactions should be added here. Morphine 23:12, 22 February 2006 (UTC)

It's all levels of understanding. COnsidering the sparse use of the half-reaction method in even Chem 1A, I think this page should just link to a page on the Half-Reaction method. Wanna make one with me? Kr5t 19:51, 2 April 2006 (UTC)

An explanation of how to balance Half-reactions is desperately needed - "Half reaction equation balancing" even redirects here, yet there's nothing! I'll check if there's any such content in Wikiversity... nope. Nothing there either! 144.136.38.19 09:46, 19 February 2007 (UTC)

Electronegativity is for atoms

Electronegativity is only for individual atoms, not allotropes of elements. Kr5t 19:52, 2 April 2006 (UTC) (This signature is a few days after I actually made this post--I didn't know how to sign posts back when I wrote this).

Mnemonic Devices

They are ugly. Good information but ugly. I’ve been thinking of ways to make them more attractive. Moving them under a separate heading might work but then they would be too far away from the original material to be of any help. Maybe bulleted… Does anyone have any suggestions? JohnJohn 01:52, 1 April 2006 (UTC)

They are, admittedly, ugly, and I apologize. Originally there was only OIL RIG, then I added LEO says GER, and that totally disrupted the flow. I think bulleted would be nice, especially since we ought to add these others: A RED(uction) CAT(hode) and AN(ode) OX(idation), and ReduCtion has a C(athode) but no A(node), and OxidAtion has a A(node) but no C(athode), both of which are for remeber which half reaction occurs at which electrode.

I bulleted them. You are right, though, they are still rather disruptive. JohnJohn 00:15, 4 April 2006 (UTC)

Oh, so thats how you bullet things! Maybe we should add some section at the end devoted to the various mnemonic devices (I'm sure there are others). Kr5t 21:25, 5 April 2006 (UTC)

I made "them" (I deleted one) small. The rest should go under a new section near the bottom. JohnJohn 16:21, 6 April 2006 (UTC)

They're back! I'm making a link to the section, so that it doesn't get ugly up there again JohnJohn 23:44, 15 September 2006 (UTC)

Oops! I don't know how to link to a section. I just deleted OIL RIG insteadJohnJohn 00:04, 16 September 2006 (UTC)

Poise

This article could use a description of what a poised reaction is, and why poise is a significant concept when working with redox. Vague references to optimal redox poise is all I have so far. -- Paleorthid 03:57, 19 April 2006 (UTC)

Oxidation and reduction properly refer to a change in oxidation number

Quote(line 10) :Oxidation and reduction properly refer to a change in oxidation number — the actual transfer of electrons may never occur. "the actual transfer of electrons may never occur" is this statement true for all types of chemical bond or only covalent bonds

Oxidize links to this page.

A typical dictionary definition of oxidize would be:

1. To combine with oxygen; make into an oxide.
2. To increase the positive charge or valence of (an element) by removing electrons.
3. To coat with oxide.

By linking oxidize to Redox we are ignoring the broader definition.

Gregogil 19:48, 5 February 2007 (UTC)

Thank you for your suggestion! When you feel an article needs improvement, please feel free to make those changes. Wikipedia is a wiki, so anyone can edit almost any article by simply following the Edit this page link at the top. You don't even need to log in (although there are many reasons why you might want to). The Wikipedia community encourages you to be bold in updating pages. Don't worry too much about making honest mistakes — they're likely to be found and corrected quickly. If you're not sure how editing works, check out how to edit a page, or use the sandbox to try out your editing skills. New contributors are always welcome. DMacks 19:55, 5 February 2007 (UTC)

Fenton's Reagent

Adding the reactions of H2O2 and Fe together is misleading since it leads to fenton's reagent. Why not use an example that is real? wikipedia says on http://en.wikipedia.org/wiki/Fenton%27s_reagent that

(1) Fe2+ + H2O2 → Fe3+ + OH· + OH−

(2) Fe3+ + H2O2 → Fe2+ + OOH· + H+

In the net reaction the presence of iron is truly catalytic and two molecules of hydrogen peroxide are converted into two hydroxyl radicals and water. The generated radicals then engage in secondary reactions. Iron(II) sulfate is a typical iron compound in Fenton's reagent.

Here is something else interesting according to wikipedia on http://en.wikipedia.org/wiki/H2O2

Oxidant Oxidation potential, V Fluorine 3.0 Hydroxyl radical 2.8 Ozone 2.1 Hydrogen peroxide 1.8 Potassium permanganate 1.7 Chlorine dioxide 1.5 Chlorine 1.4

I read somewhere that fenton's reagent occurs under acidic condition with about a pH of 3 to 6. Then a much more powerfull oxidizing solution occurs. Why not pick an example that is true in reality and not oversimplified freshman BS