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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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263 views

Finding all Chemical Reactions Given Products and Reactants

Suppose only a set of chemical formulas is given. How can you find all mathematically possible chemical equations whose educts and products are only from this set? Take e.g. the set $\{ \ce{C, H2, O2,...
2
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0answers
27 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 / ...
3
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0answers
33 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 ...
3
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0answers
29 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 , ...
0
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2answers
98 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. ...
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0answers
29 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 ...
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0answers
17 views

How to deal with coordinate bonds while dealing with formal charges?

When we calculate the formal charge of an atom in a molecule we consider the non-bonding pair as 2 electrons and any covalent bond as 1 electron. Ok then what about dative bonds,how many electrons do ...
2
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0answers
25 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 ...
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0answers
68 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 ...
0
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1answer
34 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 ...
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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
68 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 ...
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1answer
53 views

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

What happen if KMnO4/H+ added to phenylethanoic acid oxidation?
2
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1answer
28 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 ...
1
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1answer
36 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 ...
1
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1answer
52 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 ...
3
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1answer
64 views

Hydrate decomposition equation steps

When a hydrate decomposes it loses water molecules in steps. Does each step have a chemical equation? If so is the following equations for decomposition of cupric sulfate hydrate correct? $$ \begin{...
-2
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1answer
62 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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1answer
145 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 ...
0
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0answers
61 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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1answer
208 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 ...
1
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2answers
25 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 ...
1
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1answer
55 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
39 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
50 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
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1answer
95 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 ...
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0answers
31 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 ...
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0answers
27 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
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 ...
3
votes
1answer
152 views

What is the mechanism of azulene synthesis?

In the Organic Syntheses preparation of azulene (http://www.orgsyn.org/demo.aspx?prep=CV7P0015) there are two reactions. First is a clevage of the C-N bond in pyridine and the second one is the ...
0
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1answer
126 views

what the solution of this problem, negative absorbance values in UV-vis spectrum

In my project, I take the UV-visible spectrum of reaction between pyridinium chlorochromate and N-acetylcysteine. In some wavelengths, the absorbance value is negative for example it is (-0.006, -0....
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1answer
130 views

Mechanism for Bial's test

In biochemistry laboratory, it's common for undergraduate students to perform identification of carbohydrates and its functional groups. Bial's test, a method to check if any pentose is present, is ...
0
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1answer
68 views

Reaction mechanism for the conversion of acyl hydrazide to acyl azide

How is an an acyl hydrazide converted into an acyl azide in the presence of $\ce{HNO2}$? According to me, the $\ce{-NH2}$ group of hydrazide will get converted into $\ce{-N2+}$ through $\ce{HNO2}$. ...
2
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2answers
77 views

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?
0
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1answer
60 views

Effect of substituents on Ullmann reaction

This question that I recently encountered asked what the most suitable substrate for the Ullmann reaction would be. The answer given is (b) but I think it has to be (d) as the nitro group acts as EWG ...
0
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1answer
98 views

Nucleophillic addition vs SN2

The following question came in Paper 2 of JEE Advanced 2014- Here we have $\ce{CH3-}$ as the nucleophile. There are 2 possible attacks: SN2 type attack on the chlorine group. Nucleophilic addition ...
2
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0answers
43 views

most frequently used organic (name) reactions

The situation: Beside the relevant inventory in the Merck index, organic-chemistry.org lists 243 name reactions (as counted on 08-Feb-2018), the compilation by Kurti and Czako includes "250 selections"...
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2answers
48 views

Perpendicular orbitals in aryl and vinyl carbocations? [duplicate]

This point (iv) has been given under reasons for extremely low reactivity of aryl and vinyl halides. I cannot understand it. First of all, isn't the positive carbon atom in phenyl as well as vinyl ...
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1answer
52 views

Why is the carbanion resonance structure being used in the aldol condensation mechanism?

In the above mechanism's first step, what motivates the use of the carbanion resonance structure of the enolate ion if the negative charge is better localized on the more electronegative oxygen? Edit:...
2
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2answers
166 views

How does di-isobutylaluminium hydride ( DiBAl-H ) reduces carboxylic acid

$\text{DiBAl-H}$ reduces by electrophilic attack and provides hydrogen by $\text{H}^-$ transfer. Unlike $\text{LiAlH}_4$ it does not directly provide $\text{H}^-$ ion. So it should not undergo acid ...
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0answers
67 views

Acid catalyzed enolization and alpha hydrogen

In acidic catalyzed enolization of butan-2-one: We have 2 alpha hydrogens available. From the mechanism of acid catalyzed enolization there is a certain carbocation character at the carbonyl carbon ...
7
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1answer
63 views

Bond cleavage of 3 membered cyclic ring on heating

I was told to propose a mechanism for the following conversion: One obvious step is the conversion of cyclic ketal to ketone because of acidic conditions. But I am unable to understand how the three ...
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2answers
194 views

Order of Nucleophilicity

I know this question has been asked many times but I need to confirm this doubt which has been pestering me for the past few days. Suppose in an $\mathrm{S_N2}$ reaction (in polar aprotic solvent) we ...
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1answer
50 views

Fragmentation involving formation of enamine

I have a problem on fragmentation which requires mechanisms involving formation of an enamine from a cyclic ketone and cyclic secondary amine. This then reacts with a cyclic aldehyde via conjugate ...
2
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1answer
403 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 ...
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0answers
70 views

Steric Factors on reaction with grignard reagent

I was asked to find the products X and Y. For the product X,Here the grignard reagent and even the carbonyl substrate was too sterically hindered to approach the carbonyl center so no reaction would ...
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1answer
101 views

Simple soda–lime decarboxylation

This is my homework question I tried it hard the question is as follow: I attempted it as follow: According to my understanding as acid base reaction are fastest the carbanion will gain a $\ce{H+}$. ...
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2answers
93 views

How do dibromopyrazolones undergo base-promoted decomposition?

I was not sure but seeing the base as NaOH I used the fact that it will take most acidic hydrogen that is N-H and electron pair will come over it and it will resonate from two sides. I could make upto ...
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0answers
98 views

Kolbe's electrolysis of acetylenedicarboxylic acid

I have been wondering what this reaction would lead to? The ethyne diradical can't dimerize because triple bonded cyclic structures don't form until 8 carbons. And even if it polymerizes I find no way ...
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0answers
39 views

Should I use MCPBA here?

I came across a question that asked for a method to convert propene to glycerol. I used the method in the pic, but I'm worried about two steps- Step-2, This reaction is just made up by myself! I'm ...