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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What is the mechanism of this reaction? Why is one product preferred over the other?

This was in a paper I gave. I want to know the mechanism by which both of these products will be formed and why is the 1st one the major product. My thinking is that the -OH group will be converted ...
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Etard's reaction

My textbook says the following on Etard's reaction: Now, if the alkyl group attached to benzene is an unsymmetrical or branched alkyl group, such as this: What will be the reaction product(s)? Which ...
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Calculating Heat of Solution of a Compound comparing to other compound data

For example if I have a table with these data How can those data be compared with each other to find heat of solution of $\ce{KI}$?
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Mechanism of reaction of ketones with isoalkanes under conc. sulfuric acid and heat

Taken from the book of GOC by Dr. O.P Tandon, Himanshu Pandey, Dr. A.K. Virmani, Can anyone elaborate on the mechanism?
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Reaction of naphthalene with sodium dichromate/sulfuric acid

I recently came across a question where naphthalene undergoes oxidation with sodium dichromate in presence of sulfuric acid. The given options were benzoic acid, phthalic acid, decalin, and tetralin. ...
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Chemistry Equations [closed]

How do I know what the equation of a reaction is without knowing what the products are? Am i meant to do trial and error and just guess? Eg: When 3.4g Pentane was burnt in excess oxygen, 165kJ of heat ...
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1answer
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Ethyne reaction with HCN (red hot Fe) and CH2N2 (cold ether solution)

I have tried this and according to me $\ce{C2H2 + HCN -> C5H5N (pyridine)}$ and $\ce{C2H2 + CH2N2 -> C3H3N2H (pyrazole)}$ But according to my teacher the case should be vice versa, i.e. $\ce{...
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Question about Oxygen Managment [duplicate]

I am working on ideas for a more hard Si-Fi, and I am wondering through what processes one could theoretically take the carbon dioxide we breath out and break it down into Carbon and Oxygen. I am ...
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If rate of SN1 is more does that automatically mean rate of SN2 is less, and vice versa?

If I have a list of compounds and I compare their SN1 reactivity, for SN2 reactivity, is it correct to use the same list but order inverted? Are there any exceptions?
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Comparing rates of substitution reactions

The following question was asked in an exam I gave recently Compare the overall rates of the following substitution reactions $$\ce{CH3Cl ->[OH-][Weak P.A.S] CH3OH}$$ $$\ce{CH3CH2Cl ->[OH-][ ...
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Reaction of cyclooctatetraene with sulfuric acid

Problem The correct statement is (A) P & Q are aromatic compound and Q has $\mathrm{sp^3}$-hybridized carbon atom. (B) P is aromatic with 10 π electrons and Q is aromatic with 2 π electrons. (C) ...
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Why do different products form when alkali halide reacts with zinc in polar protic and aprotic solvents?

Let's take an alkali halide such as $\ce{CH3CH2Cl}$ the two reactions in polar protic and aprotic solvents are as follows: $$ \begin{align} \ce{CH3CH2Cl &->[Zn, CH3OH] CH3CH3}\tag{R1} \\ \ce{...
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How does the multi-level combustion of incense sticks work?

When you ignite an incense stick, there is an initial stage where a flame exists atop the stick (similar to a candle or a match stick). When this flame is put off, the stick combusts slowly, similar ...
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Reduction of nitrobenzen using LiAlH4 [closed]

Can you please explain why isn't nitrobenzene reduced to aniline but turns out as azobenzene on reaction with LiAlH4? Please explain the mechanism.
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Formation of enamine for unsymmetrical cyclohexanone derivatives

Question: Answer given: D My answer: C My reasoning - I outlined the following steps in the reaction: Nucleophilic attack of pyrrolidine on the carbonyl, leading to the carbon atom now having one $\...
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Does the nucleophilic substitution in an acid chloride always proceed through a tetrahedral intermediate?

I am a beginner in organic chemistry and would like to ask for the mechanism for the nucleophilic substitution of carbonyl groups from acid chloride - especially regarding the tetrahedral intermediate?...
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Why dont the zinc formed from reaction of ZnO with C , further react with O2 present in air again? [duplicate]

In equation ZnO+C---> Zn+CO (class X NCERT) How Zn in product is formed purely as metal? Shouldn't the zinc that form further react with O2 in air, thus forming ZnO over and over again and no pure ...
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Making bioplastic at high school level chemistry using PLA/Starch blends

I'm currently working on a high school chemistry essay about biodegradable plastics. I know that there is an easy way to synthesize Thermoplastic Starch (TPS), a starch-based bioplastic using glycerol ...
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1answer
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What happens in a unimolecular reaction? [closed]

Molecularity is defined as the number of molecules required to collide simultaneously to form a product in an elementary reaction. In a unimolecular elementary reaction, do two molecules of the same ...
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Does amide ion prefers to act as a base than a nucleophile?

In this question, I think that amide ion, being a good nucleophile should attack on the terminal carbon through $\mathrm{S_N2}$ mechanism to form compound (c), but the answer given is (b), and the ...
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1answer
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Does Ei or pyrolytic elimination reaction undergo carbocation rearrangement?

I've read about E1 reaction (unimolecular elimination reaction) which forms the most stable carbocation first and then undergoes the elimination. Ei is also mentioned to be "unimolecular" in ...
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Dehydration reaction of an alcohol, 2,3-dimethyl-2-phenylbutan-1-ol, with conc. sulfuric acid (at high temperature)

What's the major product of the dehydration reaction of 2,3-dimethyl-2-phenylbutan-1-ol with conc. $\ce{H2SO4}$ (at high temperature)? I am aware that in this reaction $\mathrm{E}$1 mechanism will be ...
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1answer
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Is there any specific conditions for Neighbouring group participation?

I got to know about what neighboring group participation is, but does it always occur if there are lone pair donating groups in beta or delta positions. Or does it only occur in some kind of medium or ...
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Which is better leaving group out of iodide and water?

In hydrolysis reaction of an tertiary alkyl halide , $\ce{H_2O}$ will replace the $\ce{I-}$ through $\ce{S_N1}$ mechanism and then $\ce{H+}$ will be removed from $\ce{H_2O}$ in order to form an ...
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How exactly does UV light break bonds?

For example, in the photochemical decomposition of hydrogen peroxide, the weak $\ce{O-O}$ bond is broken by UV light. Ultraviolet light can also dissociate relatively strong bonds such as the double ...
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Electrophillic susbtitution of bromine on styrene and cinnamic acid in the presence of FeBr3, a Lewis acid

Bromine gas, in the presence of $\ce{CCl4}$, undergoes on addition reaction at the double bond in both styrene and cinnamic acid, illustrated below. Styrene: Cinnamic acid: Bromination of benzene in ...
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When does bimolecular nucleophilic substitution reaction take place in phenyl group containing compounds?

We were studying SN Mechanism, and our professor gave us a question to identify the SN, mechanisms which would happen in the given compound. They were $\ce{CH3Cl}$, $\ce{PhCH2Cl}$, $\ce{Ph2CHCl}$, $\...
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Isomerisation Reactions of Alkyl Halides

My organic chemistry textbook says: Haloalkanes on heating at 573K or in presence of anhydrous at low temperature undergo molecular rearrangement to form an isomeric haloalkane. I noticed a ...
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SN1 reaction of alkyl halides

I was going through Peter Sykes organic chemistry where I came across a section where the author is saying: For halides that do not readily undergo SN1 attack ,this can be promoted by use of silver ...
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1answer
107 views

Which step is the rate determining step in Benzyne mechanism - Elimination or Addition?

I have this doubt for a while now: How can we compare the reactivity of two compounds towards benzyne mechanism, which have different leaving groups (E.g. chlorobenzene and bromobenzene)? To know this,...
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Relation between common ion effect and the temperature of the solution [closed]

Adding extra Na+ in a saturated NaCl/water solution decreases the solubility of NaCl. How does this exactly happen? AFAIK, the solubility of a solid only decreases with the temperature of the solution....
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Mechanism of Wiliamson Synthesis

I was studying about Williamson's Synthesis, and my textbook had the following statement: Williamson's Synthesis is a nucleophilic substitution reaction and proceeds via $\ce{S_N2}$ mechanism. Then ...
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In benzyne intermiediate of anisole why -I effect of OCH3 is considered not +M effect of it?

Here they considered -I effect of $\ce{OCH3}$ so carboanion is stable at orthroposition; But $\ce{OCH3}$ also shows $\text{+M}$ effect if $\text{+M}$ is shown carboanion will be stable at meta ...
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Why is nitrate anion substituted but bromide anion is not in Von Richter reaction?

In Von Richter reaction which is a nucleophilic aromatic substitution. As according to this source, there is only a 37% yield of the product.I want to know what are the competing side reactions which ...
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Elimination reaction mechanism decision (order = 1 or 2)

Match the following: \begin{array}{} & \textbf{Column I}&&\textbf{Column II} \\ \text{(A)} & \ce{CH3-CHBr-CD3} \text{ on treatment with alc. KOH gives}& \text{(P)}& \text{E1 ...
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Why does this ring contraction take place in the following nucleophilic substitution? [closed]

While attempting this problem I thought that P1 would simply be Bromine getting substituted by OH through nucleophilic substitution. P2 would give a product formed through ring expansion as a 4 ...
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Determining if the product would be cis or trans after an anti elimination on fischer projections

I find these kind of problems really confusing for some reason, but I saw a way on the web and tried doing it that way: I considered the basic Fischer operations (Vertical: Below the plane of paper, ...
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Determining the leaving group for substituted benzene in Aromatic nucleophilic substitution

I could figure out that After the substitution of one of the halogens, with the $\ce{-OCH3}$ group(Electron donating group), the ring would be deactivated towards nucleophilic substitution hence the ...
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How many equivalents of Grignard reagent does a nitrile group consume?

I was looking at reactions of grignard reagent with certain kinds of compounds and came across it's reaction with nitrile group: What I was wondering is what if we don't react the Imine formed after (...
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What would be the order of reactivity of these compounds in Sn1,Sn2,E1 and E2 reactions? [duplicate]

My problem is that these compounds seem as if their Sn1 and E1 reactivity are identical as the carbocation would of similar nature and stability. For the Sn2 part the first compound seems to have a ...
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Why is chlorosulfite a good leaving group?

I came across the following website article[1]: I understand the mechanism and also get the fact that this is nothing but an experimental result but why does the $\ce{ClSOO-}$ group departs ...
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Analysing reaction with chair conformation of substituted cyclohexane

Why doesn't Iodine liberate in the following reaction? (A) Inadequate ring size (B) Two Bromines are in equatorial positions (C) Steric hindrance of t-butyl group towards attacking $\ce{I-}$ ...
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What is role of copper powder, calcium chloride and cuprous chloride in the SN1 reaction of hydrochloric acid with propargylic alcohol?

For the synthesis of a 2H-cromene from a phenol I need to prepare 3-chloro-2-methyl-but-1-yne from the corresponding alcohol 2-methylbut-3-yn-2-ol. This reaction could be seen as a simple $S_\text N1$ ...
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When does reaction of alcohol with alumina give ethers and when an alkene?

This problem given in my book confused me a little bit: when an excess of ethyl alcohol vapour is passed over heated alumina ($250^\circ$C), the main product is? I read that this reaction gives an ...
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What is the major product in the reaction between 4-chloropentanal and lithium aluminium hydride?

What would be the major product between 4-chloropentanal and $\ce{LiAlH4}$? After the reduction of the aldehyde, would the hydroxyl group formed at $\ce{C-1}$ attack $\ce{C-4}$ causing cyclization to ...
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The dependency on electron density in the reactivity order of electrophilic and nucleophilic additions

It is well-known that for electrophilic addition across an alkene, the reactivity increases when intermediate carbocation is more stable (eg. addition of $\ce{HBr}$ or acid-catalyzed addition of $\ce{...
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In the mechanism of Cannizzaro reaction, how do we rationalize hydrogen acting as leaving group? [duplicate]

Mechanism of Cannizzaro from wikipedia I am trying to understand how to rationalize in the first step of third row that the hydrogen act as a leaving group and a nucleophile. After googling, I found ...
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Why is there a phenyl shift in this reaction?

Why is there a phenyl shift in this reaction. I believe that the +R effect by 2 phenyl groups would be better than the +R effect by oxygen because of its lone pair. Can somebody please confirm?
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How would this reaction occur through free radical substitution?

So, I was trying to solve this through free radical substitution: (Side note, the (ac) means (aq)) The best product I managed to do/think was the following: However, according to what I've seen, it'...
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Why does a methyl shift occur during the pinacol-pinacolone rearrangement?

Why does a methyl shift occur during the pinacol-pinacolone rearrangement? I was told that methyl shift is done to stabilise the carbocation but here we are shifting the ...

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