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Questions tagged [oxidation-state]

Oxidation state is a concept, which assigns hypothetical charges to atoms in compounds. This tag should be applied to questions which relate to that concept or to oxidation states in atoms of compounds.

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Reference for electronegativities of different metal oxidation states

A long time ago I was researching the effect of the self regulatory response in Fe and Co. I found that my results made sense based on the idea of the electronegativity of the ions considered. I found ...
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Unusual oxidation numbers for alkaline earth metals?

Are there compound of alkaline earth elements showing unusual oxidation numbers? For the sake of the question, every oxidation number different from +2 counts as unusual, most exciting would be ...
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Are there known compounds of caesium with oxidation number >1?

Given that the left neighbor of caesium, xenon, does have fluorides and oxides, it is not inconceivable that caesium can have oxides or fluorides with an oxidation number higher than 1. Are such ...
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How to stabilize oxidized vitamin C (dehydroascorbic acid) for optimum shelf life [closed]

Converting ascorbic acid to dehyroascorbic acid is somewhat of a simple process. It seems the hard part is stabilizing the DHA after conversion for a credible shelf life due to rapid deterioration ...
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41 views

How to find oxidation state of Co and Cr in [Co(NH₃)₄(NO₂)₂][Cr(NH₃)₃(NO₂)₃]?

Which of the following options represents the oxidation state of $\ce{Co}$ and $\ce{Cr}$ in the given complex? $$\ce{[Co(NH3)4(NO2)2][Cr(NH3)3(NO2)3]}$$ (A) $2, 3$ (B) $3, 2$ (C) $3, 3$ ...
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Finding the n-factor of C₂O₄²⁻

In the reaction $\ce{C2O4^2- → CO2}$ the $n$-factor of $\ce{C2O4^2-}$ is: So I think the answer to this question is $2$ because in $\ce{C2O4^2-}$ the oxidation number of carbon is $+3$ and in $\ce{...
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Negative oxidation state

Why doesn’t aluminum have negative oxidation states? In almost all compounds of aluminum which I know of has positive oxidation state. It has valence EC [Ne] 3s2 3p1 , my teacher told it usually ...
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42 views

Why oxidation state decreases

oxides of group 1 elements are Li2O , Na2O2 , KO2 , RbO2 Oxygen’s oxidation state in each compound is -2 , -1 , -1/2 ,-1/2 respectively I.e oxide-> peroxide-> superoxide my question The oxidation ...
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Why do heavier d block elements are more stable in higher oxidation states than lighter d block elements? [duplicate]

I read that it is because it is easier to ionise the elements as the electrons involved are those of d orbitals which have same degeneracy. First of all, i found it very vague. Secondly, what about ...
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25 views

Reactivity of Ni Vs. Pd - available oxidation states

I'm hoping someone can help me tighten up my understanding of the origins of the differences between Ni and Pd catalysis. I understand that Ni has higher charge density and this is the reason for it'...
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Can an element have variable oxidation states in a compound?

Take propanoic acid for example. If I assign oxidation states to the 3 carbons in it using the idea that the more electronegative element gets all the electrons in the bonds it makes, the 3 carbons ...
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1answer
264 views

How to determine the greatest d orbital splitting?

This question comes specifically from an IB Chemistry HL Paper 1 in May 2018 TZ1, namely question 8. Which complex has the greatest d orbital splitting? It gives 4 Complexes $\ce{[Fe(H_2O)_6]^{2+}}$,...
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2answers
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Why is phosphorus (v) oxides molecular formula P4O10 and not P2O5 [duplicate]

I understand that the name derives from the empirical formula; however, I do not understand why it does not exist as $\ce{P2O5}$. Is there a compound that exists with this as its molecular formula?
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101 views

Unusual oxidation states of alkali metals

When going through list of oxidation states on Wikipedia I encounterd there that sodium, potassium, rubidium and caesium exhibit oxidation states of -1, but not lithium, even though its ...
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296 views

Why BiCl5 isn't stable?

I read this in a textbook: $\ce{Bi(V)}$ is very unstable and is a good oxidizing agent. Why does it happen that way? Is it because in $\pu{+5}$ oxidation state $\ce{Bi}$ pulls in more electrons ...
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1answer
230 views

What is the oxidation state of bromine in BrO3?

I came across this compound $\ce{BrO3}$ in my textbook, and was trying to find the oxidation state of bromine. This is how I proceeded: Since this is not a superoxide or a peroxide, or any other ...
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Is the reaction involving a proton transfer a redox reaction?

$$ \begin{align} \ce{H2S (aq) + NH3 (aq) &→ NH4+ (aq) + HS- (aq)}\tag{1}\\ \ce{Pb(s) + 2 FeCl3 (aq) &→ 2FeCl2 (aq) + PbCl2 (aq)}\tag{2} \end{align} $$ Which of the following statements ...
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164 views

Oxidation states of boron

I have just been looking at https://en.wikipedia.org/wiki/List_of_oxidation_states_of_the_elements and found that boron has a -5 oxidation state. I would like to know which boron compounds form ...
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1answer
34 views

Identifying if reaction is reduction or oxidation. Is there an error in this question?

I am looking at this reaction: I am trying to determine if it is reduction or oxidation. In the initial molecule I calculate the overall oxidation numbers as: ...
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1answer
66 views

Can superoxide ion act as a ligand in a similar fashion as peroxide?

There is a question in my chemistry book: Find oxidation state of platinum ion in the complex $\ce{[Pt(O2)(en)2Br]+}$. My books says that there is peroxide, but I want to ask why it is peroxide? ...
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1answer
84 views

Pale blue species forming during electrolysis of NaHCO3

I have a solution of 3500 ml $\ce{H2O}$ + 454 g $\ce{NaHCO3}$ in electrolysis at a potential of 12.5V using a lead anode and copper cathode. The surface areas aren't measured but they are enormous. I ...
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Comparing the number of oxidation states of Vanadium and Arsenic

USNCO 2004 Question 45 states: Which element exhibits the greatest number of oxidation states in its compounds? (A) Ca (B) V (C) Cu (D) As I ruled out Ca, as I know it only exists as +2. I ...
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Oxidation state of Mn in MnO₄⁻

I have tried to understand what the oxidation state for Mn in $\ce{MnO4^-}$ is. So far i have understood that O have the oxidation state of -2 so because there is 4 O the number turns to -8. What ...
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Which is more reactive, chlorine radical or chloride ion?

Ions are very reactive for obvious reasons (i.e. Coulomb force); $\ce{Cl-}$ ions will be very quick to form an ionic bond with positive ions (unless inhibited, e.g. through being in a solution; let's ...
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122 views

Oxidation states for covalent compounds [duplicate]

Yesterday, I came across $\ce{SO2}$ and was supposed to write the reduction and oxidation half reactions. However, I do not understand the reason why S is assigned the oxidation number of 4+. Oxygen ...
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95 views

Oxidation state of N in NO from resonance

I know from a textbook that nitrogen has an oxidation state of +II in NO, and this is easily verified if O is assigned -II. However, if one looks at the resonance structure and assigns covalent ...
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1answer
55 views

My confusion regarding Hydrogen peroxide

In Hydrogen peroxide, the oxidation number of oxygen is "-1" instead of "-2". But it seems to me that, the oxygen atoms have '-2' as their oxidation number as each oxygen atom here is connected to a ...
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1answer
604 views

Oxidation No. of Fe and NO in Nitroprusside ion [duplicate]

For the complex $\ce{[Fe(CN)5NO]^{2-}}$ wikipedia cites that the oxidation no. of Fe is +2 and that of NO is +1. CN being -1 the net charge thus becomes -2. However at certain places I read that NO is ...
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2answers
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Materials used in cooktop heating element, and reason for black appearance

I have been interested in the structure of heating elements/coils used in cooktops. I am referring to something such as in the following picture: I have a cooktop at home with such elements, and at ...
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1answer
155 views

Stability of 3d metal fluorides and iodides in different oxidation states

I read that the fluorides of 3d metals in lower oxidation states, e.g. $\ce{VF2}$, $\ce{TiF2}$, and $\ce{CuF}$ are thermodynamically unstable. For example, $\ce{CuF}$ disproportionates to $\ce{Cu + ...
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117 views

How to predict ease of oxidation or reduction for a given oxidising or reducing agent? [closed]

I have never understood which agent will be able to oxidize or reduce which type of reactants and yield which type of products will be formed. For example I want to know about DIBAL-H and how is it ...
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2answers
151 views

Are such high oxidation states as reported by Vojovodic et al. possible?

I am a student in theoretical chemistry and I am confused about the paper: Trends in adsorption of electrocatalytic water splitting intermediates on cubic $\ce{ABO3}$ oxides (Montoya, J. H.; Doyle, A. ...
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0answers
107 views

What are the oxidation states of galium and arsenic in GaAs semiconductor?

According to the book I'm referring to ("S.M. Sze Semiconductor Devices"), gallium has an oxidation state of +1 and arsenic has that of -1. This should not be possible as each of these elements forms ...
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42 views

Why is this redox reaction possible?

I have the redox reaction $\ce{N_2H_4 {(g)} + N_2O_4 {(g)} -> N_2 {(g)} + H_2O {(g)}}$. In $\ce{N_2O_4 {(g)}}$, the oxidation state of nitrogen is $+4$. In $\ce{N_2 {(g)}}$, the oxidation state of ...
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Why is it a reduction from a ketone to an alcohol? [closed]

Why is it a reduction from a ketone to an alcohol (using $\ce{LiAlH4}$)? I'm not able to figure out the oxidation state of carbon.
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Why is the oxidation state of Co -1 in [Co(CO)4]-?

In $\ce{[Co2(CO)8]}$, most people say the charge of $\ce{Co}$ is 0. How does it become $\ce{[Co(CO)4]-}$? Most answers would say that $\ce{Co}$'s charge becomes -1. How does this work? -1 is not ...
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342 views

Why does iron lose exactly 3 electrons in oxidation?

I'm not a chemist, but I have this question. Why does iron (Fe atom) lose three electrons when exposed to oxygen for the first time? Why doesn't it lose less than or more than three electrons?
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581 views

Why is oxidation number of Ba not +2 in this case? [closed]

According to redox rules, column 2 elements (alkali earth metals) have an oxidation number of +2, but in this reaction: $\ce{Ba + Cl2 -> BaCl2}$, the oxidation number of $\ce{Ba}$ changes from $0$ ...
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1answer
31 views

How does something like elemental oxygen oxidize anything if each atom's valence shell is full? [duplicate]

Been learning in biology about $\ce{O2}$'s role as an oxidizing agent, but I don't really understand how $\ce{O2}$ can take electrons from anything if it's not reactive....
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Is it possible for the iodine atom in periodate ester to be octavalent?

Recently, I was reading Clayden's Organic Chemistry (2nd ed.) and I chanced upon this diagram on p. 443 (as shown below) showing an octavalent iodine in the periodate ester. I found this rather ...
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Why oxides with the element in higher oxidation state are more acidic

We see this trend of acidic-basic property of oxides in most cases: $\ce{Mn2O7}$ is acidic, $\ce{MnO}$ is basic, the intermediate oxides are progressively less acidic and more basic, as the oxidation ...
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1answer
60 views

Prevent/Slow down oxidation of organic material

I'm having the hobby to draw paintings with the tea I drink trough the day. Usually I pour a tablespoon of the hot tea away, wait until it dries and gets more concentrated, so the colour is more ...
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1answer
145 views

Can Cl(g) cause quick rusting? [closed]

I'm actually digging in something that comes from Syria... How does Chlorine cause metal to get rusted? It's full of pictures of rockets (allegedly filled with chlorine gas) that are all rusted. In my ...
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1answer
306 views

Is the reaction of SiC and H2O a redox reaction?

In the reaction: $$\ce{SiC + 2H2O <=> SiO2 + CH4}$$ The oxidation state of Si is +4 in both SiC and SiO2, while the oxidation state of carbon is -4 in both SiC and CH4 (confirmed by this). Here ...
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1answer
566 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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1answer
318 views

Bond strength of pi acceptors and metals with filled d(pi) orbitals

I was reading in The Organometallic Chemistry of the Transition Metals (Robert Crabtree) that lewis acids like BF3 often accept electrons from d(pi) orbitals. Is this generally true for all pi ...
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2answers
585 views

In the blue bottle experiment, will it eventually be “used up” after repeated use?

The blue bottle experiment is a bottle half full of a colorless solution (dextrose, KOH, and methylene blue, in the version that I saw) and air that, when shaken, turns blue through the methylene blue ...
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1answer
87 views

Dumb Question about Oxidation

This is probably a really dumb question, but I can't find a clearly spelled out for me yes or no answer by searching through google, so hopefully I'll get a yes or no answer her. Can metals, for ...
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817 views

How do I balance the reaction equation of zinc and nitric acid?

How would you balance the following reaction using the oxidation number method? $$\ce{Zn + HNO3 -> Zn(NO3)2 + NH4NO3 + H2O}$$ My approach: Half reactions: \begin{align} \ce{Zn &-> Zn(NO3)2}...
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Ionizing radiation and oxidation without oxidizing agents

My knowledge on this subject is a bit rusty, so excuse me if I'm asking the wrong question here. I was taking a look at my high school chemistry books from many years ago, and I noticed that reduction ...