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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11
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1answer
246 views

Formamide and Hoffmann Bromamide Reaction

I encountered a problem to identify the compound which does not give Hoffmann bromamide degradation reaction. One of the options was formamide, and it was given as the answer. Why can't formamide ...
3
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0answers
55 views

Diazo Coupling reaction with para substituted phenol?

Usually Diazo coupling occurs at para position until the para position is occupied , in which case coupling occurs at ortho position . While solving questions I found in both the cases as shown , ...
2
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2answers
294 views

Gibbs free energy in standard state vs. equilibrium

I have a problem with the definition of the standard Gibbs energy and its connection to the equilibrium constants. I think, that I've basically understood what the different equation mean but there ...
1
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0answers
33 views

How to recreate bioluminescence in fireflies in a lab?

I have several mg/mL of D-luciferin, luciferase (firefly), ATP solution (25 mmol) and MgSO4 (for the mg2+ ions). The experiment has to be done in cuvettes of 2,5 mL (if I get any results, it will be ...
0
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0answers
161 views

Iodoform on acetone gives one product?

During the Iodoform reaction of acetone why does the second iodine addition happen on the carbon that already has undergone substitution instead of the other carbon?
0
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1answer
110 views

A simple question about the direction of a chemical reaction

I do not know much about Chemistry and whatever I knew has become rusty. I have a very simple query. I take a beaker containing pure $\ce{H2SO4}$ solution and immerse a rod of pure $\rm Zn$ into it. ...
2
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0answers
34 views

What is the mechanism of platinum as catalyst poisons on alumina?

I'm wondering if anyone knows by what mechanism is platinum (or other noble metals) catalyst on alumina substrate poisoned? Presently, I'm using platinum on alumina to decompose a hydrogen peroxide / ...
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0answers
89 views

Predicting the products obtained after addition of bromine and then elimination using alcoholic KOH

If we have an alkene reacting with bromine, then I know that the the reaction happens by a cyclic intermediate. But if we add alcoholic KOH to the products formed, then what will be the major products ...
3
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0answers
52 views

Chugaev and Selenoxide Elimination giving different products

In class we are going over intramolecular elimination. In this question I will provide two similar reactants that provide a different mixture of products. The chugaev elimination gives a 50/50 ...
1
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0answers
33 views

Deuteration of following enone - mechanism?

What happens when the above compound is subjected to DCl in MeOD? As a result of tautomerism, I'd expect at least 7H atoms, two alpha to carbonyl carbon (right side), and five at gamma position (two ...
1
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1answer
854 views

Mechanism of the Gatterman Reaction

Aryl diazonium salt on treatment with copper and the corresponding hydrohalic acid, gives the aryl halide. This reaction is called the Gatterman reaction. What is the mechanism of this reaction? Is ...
2
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0answers
29 views

Emergence of Lognormal distribution for the concentration of chemical compounds

I'm currently reviewing the literature about lognormal distributions describing/approximating the variability of a given chemical compound across different cells/ samples etc etc. The main argument ...
4
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2answers
4k views

3-step process to make propyl ethanoate from propene

I was asked to make propyl ethanoate from propene in three steps. I have access to the reactions below. Nucleophilic substitution (Both SN1 and SN2) Electrophilic addition Hydrogenation Dehydration ...
0
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1answer
40 views

What is the reason for more stable keto form to tautomerise to a less stable enol form?

In the mechanism of SeO2 I have seen that a more stable keto form first converts to a less stable enol form and then yields a diketone. I have seen many other reaction where the reactant converts to ...
21
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3answers
24k views

Why are solids and liquids not included in the equilibrium constant? What about in a reaction rate calculation?

Take for instance the reaction $$\ce{H2(g) + I2(s) <=> 2HI(g)}$$ The equilibrium constant would not include the solid $\ce{I2}$, but why is this? I have read that its concentration is a ...
7
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1answer
1k views

Which of the following para-substituted benzyl alcohols reacts fastest with HBr?

I had a question in a recent test which asked me to pick the compound that would react fastest with $\ce{HBr}$ with the options being: p-nitrobenzyl alcohol p-chlorobenzyl alcohol benzyl alcohol p-...
2
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1answer
215 views

Does the reaction of 1-bromobutane with cyanide ion follow an SN1 or SN2 mechanism?

In my textbook it's mentioned that the reaction undergoes $\mathrm{S_N2}$ mechanism. I understand that the carbon attached to the bromine is primary, but both solvents here are polar protic solvents, ...
2
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0answers
836 views

What is the reaction between diethyl malonate and hydrazine?

For the reaction of diethyl malonate with $\ce{NH2NH2}$ in aqueous medium in presence of $\ce{CH3CH2OH}$, I found two types of product with SciFinder: In presence of $\ce{H2SO4}$, the reaction ...
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0answers
18 views

Is the iodide and persulfate reaction bimolecular?

Given the following reaction in an aqueous state: $$ \mathrm{2I^- + S_2O_8^{-2}\rightarrow I_2 + 2SO_4^{2-}}$$ Is it bimolecular o trimolecular? Because two molecules of iodide react with one ...
0
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1answer
80 views

Bromination of but-3-en-1-ol in basic medium and Baldwin's rules

After formation of the bromocarbocation the alkoxide anion attacks the bromocarbocation which leads to ring formation and can proceed through two pathways 5 endo tet cyclization is disfavored but 4 ...
9
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1answer
199 views

Why would a reaction favor one isotope over another?

In my instrumentation class last semester, we were asked to read a short paper. The paper described a technique for determining whether dinosaurs were cold-blooded or warm-blooded based on the amount ...
-1
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1answer
225 views

What happen if KMnO4/H+ added to phenylethanoic acid oxidation? [closed]

What happen if KMnO4/H+ added to phenylethanoic acid oxidation?
1
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1answer
163 views

Dependence of primary alcohol oxidation on presence of water and “strong” or “weak” oxidants

It is known that the oxidation of primary alcohols can result in aldehydes or carboxylic acids. The product obtained from the reaction is described as dependent on reagents and conditions;[1] "...
1
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1answer
111 views

E-glass degradation in water

At the moment, a question puzzling me is why and how glass fibers degrade in water environment? As the degradation of the glass fibers occurs, its reduces the strength of them. As far as I know, the ...
10
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3answers
1k views

Does Wurtz reaction follow an ionic mechanism or a free radical mechanism?

In a Wurtz reaction, is the intermediate formed a carbanion or a free radical. And if can assume both mechanisms to be true, how can we decide the reactivity of a tertiary halide?
4
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0answers
2k views

Oxidation of alkenes by selenium dioxide to diketones

I know that $\ce{SeO2}$ readily affects the allylic position. The reaction mechanism of this reaction goes like this: (Source: Wikipedia; License: Public Domain) But, in my book, there's another ...
2
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1answer
30 views

Does mixing calcium dichloride and magnesium sulfate induce a reaction, and how does it affect the hygroscopy of the sample?

I have a problem with a sample made from $\ce{CaCl2*2H2O}$ and $\ce{MgSO4*7H2O}$ in about equal amounts. I took the two salts, pressed them together, and the result was a weird brine that was very wet ...
0
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1answer
286 views

The reaction of iron with sulfur to produce Iron(II) sulfide is inconvenient (for me)

I am taking a lot of iron properties this semester, but I have found some contradicting piece of information about the reaction of iron with nonmetals illustrated with two cases \begin{align}\ce{ **...
7
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0answers
15k views

Mechanism for an Étard reaction (chromium complex)

In the following reaction, a chromium complex is formed during the Étard reaction: I have the following questions: How is this complex formed? How does its hydrolysis take place? (What's the ...
1
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1answer
40 views

Why do reactions happen at all? [closed]

What makes some atoms/compounds reactive and some noble? What is the fundamental truth behind a reaction? It seems that two species can undergo number of combination to give a compound. Say Sodium and ...
6
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1answer
241 views

Conversion of benzenediazonium chloride to benzene using lithium aluminium hydride

Why does benzenediazonium chloride get converted to benzene upon reacting with $\ce{H3PO2}$ and not $\ce{LiAlH4}$ ? Also, what is the reaction mechanism of the reaction with $\ce{H3PO2}$ ? This ...
8
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1answer
254 views

What happens in the attempted diazotisation of 1,2-diaminobenzene?

Usually, $\ce{NaNO2}$ and $\ce{HCl}$ are the reagents used to generate an aryldiazonium chloride from an aniline. However, in this compound there are two amine groups adjacent to each other, so it ...
1
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1answer
84 views

Is common ion effect applicable on two strong electrolytes

Consider the nitration of benzene using mixed conc. $\ce{H2SO4}$ and $\ce{HNO3}$.If a large amount of $\ce{KHSO4}$ is added to the mixture the rate of nitration will be : Faster Slower ...
-2
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1answer
91 views

Mechanism for chloromethylation of Salicylaldehyde [closed]

Reaction mechanism for following reaction : Salicylaldehyde + formaldehyde +con. HCl $\ce{->}$ 5-(Chloromethyl)salicylaldehyde
6
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3answers
5k views

Why do we need sulfuric acid in creating alkyl bromide and not in creating alkyl iodide from alcohol and hydrogen halide?

i) $\ce{R-CH_2-OH + HBr ->[H_2SO_4] R-CH_2-Br + H_2O}$ ii) $\ce{R-CH_2-OH + HI -> R-CH_2-I + H_2O}$ What role does sulfuric acid play in the first reaction? Why are we not using it in the ...
5
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0answers
643 views

Why PI3 is not used 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 ...
0
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0answers
187 views

Preference for tin or iron in the reduction of nitrobenzene

My NCERT book(Class 12) said the following for reduction of nitrobenzene using $\ce{Sn/HCl}$ and $\ce{Fe/HCl}$ : Now, I have been following this mechanism for this particular reduction, and it seems ...
1
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2answers
27 views

Do lithium batteries 'explode'/'burn' because of the electric energy stored within?

I've been watching some videos where people show lithium ion batteries burning/exploding. What usually happens is someone punctures the battery, and a jet of gas comes out the puncture hole, followed ...
0
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0answers
28 views

Improvement of the thermal stability of hydrous zirconia by post-synthesis treatment with NaOH and NH4OH solutions

I read a paper about how researchers improved the thermal stability of hydrous zirconia by post-synthesis treatment with $\ce{NaOH}$ and $\ce{NH4OH}$.[1] While the surface area of non-treated ...
1
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1answer
50 views

Question about reactions that are always spontaneous and non spontaneous

I wanted to ask for examples of spontaneous chemical reactions meaning that their enthalpy would be negative (exothermic) and their variation of entropy would increase, therefore the Gibbs energy ...
0
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1answer
119 views

How does the proticity of an acid affect the enthalpy change of its reaction with a base?

For an experiment I've carried out a series of reactions between monoprotic bases (ammonia and potassium hydroxide) and several acids. Two of these acids were monoprotic (hydrochlori acid and ethanoic ...
3
votes
1answer
100 views

Why we should concern with A∞?

To determine the order of one reactant at pseudo concentration of another reactant the plot of $\ln(A_t - A_∞)$ versus $t$ is used. $A_t$ is absorbance of the intermediate at time $t$. $A_∞$ is ...
4
votes
1answer
9k views

How is benzene prepared from acetylene?

The mechanism of this polymerization reaction which finds its utility in the preparation of benzene in a red hot iron tube piques my curiosity. I've read this Wikipedia article on cyclotrimerization, ...
27
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4answers
28k views

Why does alcoholic KOH prefer elimination whereas aqueous KOH prefers substitution?

What is the basic difference between aqueous and alcoholic $\ce{KOH}$? Why does alcoholic $\ce{KOH}$ prefer elimination whereas aqueous $\ce{KOH}$ prefers substitution?
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0answers
47 views

Alkylation of acetophenone

When the NaOH deprotonates the hydrogen off the carbon, I thought there would be a resonance structure, with the negative charge being on both the oxygen and carbon. Since the oxygen is more stable ...
1
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1answer
20 views

store alcohol tinctured herbs in polypropylene for extended time [closed]

Can I store alcohol tinctured medicinal herbs in the 2 oz. food grade polypropylene cups (PP 5) for about a week? I would like to have several "doses" ready to go because they are taken several ...
4
votes
2answers
12k views

Why does charcoal absorb smells from the air, and where do those smells 'go' once absorbed?

I've read that using blocks of charcoal can remove some odors from the air by placing them in the vicinity of the odors. (Maybe not as efficiently as other forms of carbon, as pointed out in the ...
4
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1answer
1k views

Grignard Reagent in THF vs in Diethyl ether

While learning about the Grignard reagent I was taught this by my teacher, but I couldn’t justify why it was so.. I cannot see how Grignard reagent would react differently in basically an ethereal ...
4
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2answers
635 views

Percentage purity of Ba(MnO4)2 sample that completely reacts with given H2O2?

$\pu{40 g}$ $\ce{Ba(MnO4)2}$ (mol. wt. = 375) sample containing some inert impurities in acidic medium is completely reacted with $\pu{125 mL}$ of $\pu{3 M}$ $\ce{H2O2}$. What is the percentage purity ...
4
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2answers
1k views

Why can't all electrophiles act as Lewis acids?

We know that all Lewis acids are electrophiles but I have a confusion whether the reverse is also true. Electrophiles are molecules that are in search of electrons while Lewis acids are short of ...