Questions tagged [reaction-mechanism]

The detailed (and as complete as possible) description of plausible or observable pathways leading from reactants to products of a chemical process. This tag should be applied to questions about these processes. It may be applied to hypothetical and/or proposed mechanisms.

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23 views

Relationship between molecularity and the reaction order

Should the molecularity be equal or less than the reaction order? Consider the reaction: $$\ce{H2(g) + I2(g) → 2 HI(g)}$$ If we consider the mechanism of this multi-step reaction, the molecularity is ...
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Reaction of SeCl4 with alkene and possible consecutive reaction?

there is a reaction that confused me a bit: According to my research on SeCl$_4$, it can be used as a dichlorinating agent for alkenes. However, I am totally confused about the mechanism. I've read ...
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if not the catalyst, can the rate of reaction be infinitely high when I increase the temperature [closed]

for example, I did an experiment before, I used enzyme and hydrogen peroxide, the rate of reaction will stop increasing since the enzyme will denature under an overly high temperature, I want to see ...
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Describe the formation of the [PbCl4]2- complex ion

The $\ce{[PbCl4]^{2-}}$ complex ion is formed when $\ce{PbCl2}$ is exposed to excess $Cl^-$ ions in solution as explained here and here through the following reversible reaction: $$\ce{PbCl2(s) + 2Cl^-...
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Write the structure of the major organic product of the reaction of 1-bromo-2-methylpropane with NaOCH2CH3 in CH3CH2OH

The solution to this question was an E2 product. However I assumed the reaction would be SN2 since 1-bromo-2-methylpropane had a primary substrate. Why is the product E2? Process of thinking: (OF why ...
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Why is H2O a weaker acid than acetylacetone? Shouldn't a hydrogen connected to an oxygen be more acidic than a hydrogen connected to a carbon atom? [closed]

I recently started studying chemistry after a long pause in my education so pardon me if it is a simple question. In the organic chemistry course I am taking, the professor told us that the first ...
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What is the formula for the reaction between aqueous sodium carbonate and trisodium citrate buffer [closed]

I reacted these two in an experiment. I understand that when sodium carbonate reacts with water it forms sodium hydroxide. So, is the OH- from the sodium hydroxide that reacts with the trisodium ...
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1answer
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Acidity of thiamine - how comes hydroxide anion with pK about 15 ionizes thiamine with pK about 18?

Textbooks say removing proton from thiamine's C atom will produce a resonance stabilized carbanion which is hence bioactive. That's OK, but how comes that 1) we abstract the acidic proton with the OH ...
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Mechanism of the reaction of an alkene with excess HI in presence of CCl4

Problem Answer Question I thought of Markovnikov's rule and suggested 1,2‐diiodopropane as the the final product: Apparently, this is wrong. I can not figure out the mechanism of this reaction (...
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Can rate constant have units as 1/time?

On paper, we get the unit of rate constant as 1/time for a First Order Reaction. I wanted to know how is this practically possible? This unit implies that '1' changes per unit of time. But '1' of what ...
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How does the equilibrium shift when concentration of reactant and product are increased simulatenously

Before answering my question, take a look at this example $$\ce{2NOCl <=> 2NO + Cl2}$$ Let's suppose I have 2 mol/l $\ce{NOCl}$, 2 mol/l $\ce{NO}$, and 1 mol/l $\ce{Cl2}$ in a closed system. ...
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Hell-Volhard-Zelinski Reaction [closed]

What is the role of red phosphorus in hvz reaction? Initially I think that red phosphurus is nothing but a catalyst. But it is not a catalyst.
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Can we use PI3 in HVZ reaction?

With the help of HVZ reaction, we can get alpha-chloro or alpha-bromo carboxylic acid. But can we make alpha-iodocarboxylic acid with the help of HVZ reaction? I could not find any reference of HVZ ...
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If SOCl2 reacts with alcohols via SNi, why doesn't POCl3?

A bit of a follow-up to Why is thionyl chloride preferred for preparing alkyl chlorides from alcohols?. The reaction with $\ce{SOCl2}$ is also used instead of $\ce{PCl3}$ and $\ce{PCl5}$ when ...
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Anti Markovnikov Product with Oxymercuration - Demercuration [duplicate]

Consider the Oxymercuration - Demercuration of the following compound with $\ce{Hg(OAc)2}$ followed by treatment with $\ce{NaBH4}$ in basic medium: Here, if we go according to Markovnikov addition of ...
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Can cycloalkanes undergo electrophilic addition? If so, what is their mechanism?

Cycloalkanes have the same general formula as alkenes. Doesn't this mean that cycloalkanes can be saturated by turning into alkanes the same way alkenes use? If so, what is the reaction mechanism? In ...
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1answer
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Equilibrium with an E2 step

E2 mechanisms are known to be irreversible in general, because the forward step takes 2 species and produces three species, and a trimolecular reverse step is unlikely, purely on entropic grounds. (As ...
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Reaction mechanism of tin(II) chloride to reduce nitrobenzene to aniline [duplicate]

Does anyone know the reaction mechanism for $\ce{SnCl2}$ to reduce nitrobenzene to aniline? I can only find $\ce{Sn/HCl}$ reaction mechanism but can't seem to find any information on $\ce{SnCl2}.$ ...
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Epoxide opening mechanism [duplicate]

Consider the following reaction: Our interest is the second step. Notice that after protonation of oxygen, the water molecule attacks in an S$_{\text{N}}2$ fashion. My question is, why does this ...
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Why is it only electrons that take part in chemical reactions?

I learnt that only electrons take part in chemical reactions and the protons do nothing (neutrons are electrically neutral, so they do nothing). Why is this so if the protons are positively charged ...
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Fluorescein synthesis

What is the mechanism of the fluorescein synthesis performed by von Baeyer?
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Stereochemistry + isomer check

We start with compound M: [Please imagine green bonds as dotted bonds going into the plane] From compound M, we are told that the 3 membered ring is opened u using sodium azide yielding a mix of ...
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1answer
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Reaction between barium peroxide and hypochlorous acid

When $\ce{BaO2}$ reacts with $\ce{HClO},$ the question tells us that that oxygen, barium chloride and one other product is formed. The equation I came up with is $$\ce{BaO2 + 2 HClO -> BaCl2 + 2 O2 ...
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Synthesis of Potassium Trioxalatoaluminate (III) Trihydrate

We mixed $\ce{Al}$ powder and hot water. Then we added $\ce{KOH}$ to the $\ce{Al}$ solution and it bubbled heavily (producing $\ce{H2}$). When that was over we added oxalic acid dihydrate to the ...
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Markovnikov Rule of Alkenes

$$\ce{CH3CH(CH3)CHCHCH2CH3 + HBr ->}$$ According to Markovnikov Rule, "the rich get richer". But, as we can see the 2 carbons have the same amount of $\ce{H}$. So, what's probably the answer?
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Write the detailed, stepwise mechanism of this reaction: [closed]

I couldn’t figure out how to turn the five membered ring into 6 membered ring. Pls help
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What gas was produced in this orbiting space-balloon from 33 pounds of benzoic acid and anthraquinone? Why these two chemicals?

As pointed out in this answer, on page 4 of NASA Technical Note TND-1366 The Orbital Behavior of the Echo I Satellite and its Rocket Casing During the First 500 Days (June, 1962) says: PHYSICAL ...
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What is the mechanism of the following rearrangement? [closed]

but-1-ene with a positive charge on the fourth carbon being converted into 1-methyl cyclopropane with a positive charge on the methyl substituent. I know that the reason for this conversion is due to ...
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1answer
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Reaction of cyclohexene oxide with LDA

The question given above appeared in the 2016 Indian National Chemistry Olympiad (INChO). What I think is that the epoxide ring is being opened by a base-catalysed mechanism ($\mathrm{S_N2}$). I ...
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Why are two three-membered rings preferred to a single five-membered ring in the reaction of a dihalide with alcoholic KOH?

The given answer is 1,1-dicyclopropylmethanone: Step 1 is abstraction of acidic H by the strong base. Then, there's surely going to be anchimeric assistance. But there can be two places where the ...
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What would be the correct mechanism for hydration of ethene?

Given above is the mechanism that I drew but my textbook puts it a bit differently. It says that the ethene is dissovled in the concentrated $\ce{H2SO4}$ to form ethyl hydrogen sulphate $\ce{CH3-...
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Stability and Rate of Formation of Carbocations

Consider the dehydration reaction of the following compounds with $\ce{H2SO4}$: (a) Tert-butyl alcohol (b) 3-Methylbut-2-en-1-ol Consider the protonation of the $\ce{OH}$ group followed by the ...
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Does DIBAL-H reduce alcohol?

Does DIBAL-H reduce alcohol? I was reading an article by Rentsch and Kalesse [1] and I came across this reaction, but could not figure out how the final compound is formed: Reference Rentsch, A.; ...
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3answers
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Need reactants for a rocket [closed]

I am doing a project in chemistry at the moment to build a rocket out of materials that can be easily bought and that react strongly to create thrust. I was wondering if anyone knew a good chemical ...
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1answer
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What is the geometry of a tri-substituted methyl free radical?

My teacher explained that free radicals could have a geometry that is planar or pyramidal(tending to tetrahedral) based on whether or not it is substituted by lone-pair containing atoms. For example, $...
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Introducing n-propyl group to benzene using cyclopropane

I am studying Friedel–Crafts alkylation reactions and my textbook states the following proposition [1, p. 1090]: Another very good means of introducing $n$-propyl group is to use cyclopropane as the ...
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1answer
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When Iron reacts with any other species, how will we know that the reaction will be of Fe(II) or Fe(III) i.e. of ferrous or ferric? [closed]

Like when iron reacts with water there forms iron oxide and hydrogen but how'll we come to know which of three equation will be right equation for reaction? $$\ce{Fe + H2O → FeO + H2}$$ $$\ce{2Fe + ...
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Retro Diels–Alder reaction in synthesis of corallopyronin A

I was looking at the synthesis of corallopyronin A in the following paper by Rentsch and Kalesse: Angew. Chem. Int. Ed. 2012, 51 (45), 11381–11384. There is one reaction which is described as ...
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1answer
446 views

Hydroxyl group to free amine in polyethylene glycol using CDI?

For converting $\ce{OH}$ of methylated polyethylene glycol. The first step is converting hydroxyl group to imidazole carbamate as an active intermediate. But what about the next step? If I will add ...
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Mechanism for Lucas Test [duplicate]

In the mechanism for Lucas' Test for Alcohols, I am reading two different types. One says the first step is the abstraction of a proton from HCl, but on other references, I also see that the first ...
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Aluminum Battery with PAC setup : Rapid voltage drop problem after a charge

I am a retired man and seek for activity. I dont have background in chemistry but I want to learn an aluminum battery..the known problem is my aluminum metal get eaten and also corrosion even if using ...
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1answer
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SN2 reaction with alkyl bromide and pentanenitrile? [closed]

Is it possible to do a Friedel-Crafts alkylation on a plain alkane such as the one I've attached below, or is it only reserved for EArS mechanisms? Also, I was wondering what would happen if I tried ...
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Why use Stork enamine alkylation?

I recently learned about the Stork enamine alkylation method of adding electrophiles to the beta carboxyl position on a molecule. But I can't seem to find out why a direct synthesis is not possible (...
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What happens to concrete if you add lye to the mix?

What happens if you’re mixing concrete and you add some lye to it? Does it make it weaker, stronger or does nothing at all? I’m guessing concrete is basic so adding lye to it might expedite the ...
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Mechanism for reaction between hydrochloric acid and magnesium

Balanced equation: $$\ce{Mg(s) + 2HCl(aq) -> MgCl2(aq) + H2(g)}$$ However, Cl- is a spectator ion so the actual reaction equation is: $$\ce{Mg + 2H+ -> Mg^2+ + H2}$$ Here is my proposed ...
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Why does equilibrium for the addition of the Claisen enolate to an ester not favor the product?

I am currently reading chapter 26 of Clayden's Organic Chemistry, and a diagram for the elementary steps of the Claisen condensation with ethyl acetate in ethoxide is provided. It is obvious why the ...
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1answer
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Exergonic vs Endergonic Reactions

Problem Problem 3, concept check 8.2 from Campbell Biology [1, p. 150]: Some partygoers wear glow-in-the-dark necklaces that start glowing once they are “activated” by snapping the necklace. This ...
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2answers
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PLP-Dependent Cyclization and Decarboxylation

I am looking at Compound A (see below) and am trying to figure out a decarboxylation mechanism that results in Compound B (see below). I have come up with an internal mechanism that might work that I ...
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Reaction analogous to burning that causes cooling rather than releasing heat [closed]

Is it physically and chemically possible to design both a gas and a solid substance, such that there would be a technologically feasible initiation of a chain reaction analogous to the spark that ...

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