Questions tagged [stability]

Applied to a chemical species, the term expresses a thermodynamic property in reference to a standard, stating that one state is lower in energy than another. The tag should be applied to questions seeking answers with respect to the stability (or instability) of a certain chemical species, molecular entity and/or electronic structure. It must not be applied to questions about the reactivity of particular chemical species.

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5
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1answer
154 views

On the stabler tautomer in amide-imidic acid tautomerism

In the section on acid-catalysed hydrolysis of nitriles, this webpage has the following line of reasoning; ...the more stable amide tautomer predominates the (following) equilibrium. (credit) How ...
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Is there an enolate equivalent for enamines?

I'm learning that enolates are stronger than enamines are stronger than enols in terms of general nucleophilicity. Makes sense. But what I can't find any explanation for online is why the trend ...
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1answer
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If the ferric ion is more stable than the ferrous ion, then why is it readily reduced to the latter?

The standard reduction potential value for the ferric ion: \begin{align} \ce{Fe^3+ + e- &<=> Fe^2+} & E^\circ &= \pu{0.77 V} \end{align} The value is positive, hence it means that ...
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1answer
91 views

Stability in 3-4 membered conjugated ring [closed]

We have 3 products one is cyclobuta-1,2 diene cyclobuta-1,3 diene and the other is cyclo prop-2-en-one, we want to find the stable product out of the 3. So,the third one due to high angle strain, ...
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1answer
89 views

Among Benzyl carbocation (Ph-CH2+) and Methyl methoxy carbocation (CH3-O-CH2+), why is the latter more stable?

Benzyl Carbocation could form multiple conjugation, then why isn't that stabler? In Methyl methoxy carbocation, Oxygen donates the lone pairs but so does the double bond in the benzyl Carbocation.
3
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1answer
129 views

Stabilization of multiple bonds through inductive effects

In the conversion of m-chloroanisole to m-anisidine using $\ce{NaNH2}$ and liquid $\ce{NH3}$, apparently the reason the $\ce{NH2-}$ goes for the meta- position instead of the para position is that, in ...
2
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1answer
87 views

Choosing hyperconjugation when resonance doesn't give a reason for stability

Which of the following structures would be least stable? I initially approached it like this: As both are allylic carbocations, and that both are in fact resonating structures of the same molecule, ...
2
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1answer
84 views

Second-step activation energy in SN1 reactions

In SN1 reactions, it's known that there are generally two steps, with the first being the R.D.S step involving carbocation formation and the next having a lower activation energy. Why does the second ...
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1answer
95 views

Why is the molozonide adduct thermally unstable?

In the mechanism of alkene-ozonolysis, the intermediate molozonide adduct, which is a cyclical but symmetric molecule (shouldn't symmetry about the C-C single bond bring stability?), decomposes ...
0
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1answer
43 views

Which of the following compounds possess more than one percent enol content? [closed]

Which of the following compounds possess more than one percent enol content? I understood that stability of enols are dependent on the hydrogen bonding in the compounds. But here, what is the ...
2
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2answers
4k views

Is RS- more basic than RO-?

The basic strength is determined by the ability of an ion or molecule to accept a proton. How do I know whether RSH is more stable than ROH? (R is an alkyl group)
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2answers
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Which is more stable? A phenyl carbanion or a disubstituted vinylic carbanion?

I came across a question which asks to work out the stability order for the following species- b. c. $\ce{R2C=CH-}$ Can the lone pair on phenyl carbanion participate in resonance? If yes, then how?...
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101 views

Stabillity of ethyl, iso propyl and vinyl free radicals

Well this might seem like a dumb question but I was just wondering if any other factor would apply here as well? By simply looking at the number of hyperconjugative structures, I could easily tell ...
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25 views

How would we arrange these in the increasing order of stability? [duplicate]

Here we have three isomers of butene there structure of who I have attached: cis-butene trans-butene iso-butene I was able to figure out that the trans isomer would obviously be more stable than the ...
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2answers
79 views

How can you calculate the tendency of one compound to become another?

Excuse my inexperience with chemistry here. I've been poring over papers with terms like "Standard Gibbs free energy of formation", "Hess's Law", "standard enthalpy of ...
1
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1answer
723 views

How is Gibbs free energy related to stability? [closed]

I have been learning thermodynamics for quite some time and I fail to relate Gibbs free energy and stability. For example, how do I compare stability of metal oxides using the following data? Also, do ...
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2answers
655 views

What is the definition of thermodynamic stability?

The term thermodynamic stability is used on this site, but I can't find a good definition. Is is a quantitative or a qualitative concept? Does it apply to a single compound, or a pair of compounds? ...
4
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1answer
358 views

Why is oxygen more stable than oxygen dication?

According to molecular orbital theory (MOT), $\ce{O2^2+}$ has a greater bond order than $\ce{O2}$ and two less antibonding electrons. So why is molecular oxygen $\ce{O2}$ more stable than the ...
3
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1answer
73 views

Deciding which group twists out of the plane when ortho effect takes place

I'm going to take a few stills from 3D conformers of the following compounds available on PubChem in which ortho effect is applicable to show what I'm referring to. 2-Nitrobenzoic acid: N,N-Dimethyl-...
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How to decide the order of stability of allylic carbocations when comparing to benzylic carbocation?

I was going through my organic notes and found this order of stability of carbocation: 3° benzylic > 2° benzylic > 2° allylic > 3° alkyl I understand that all this is explained on the basis ...
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2answers
11k views

Are geminal disubstituted alkenes more stable than their cis/trans isomers?

I know for a fact that cis alkenes are less stable than trans alkenes due to steric repulsions. But what bugs me is the fact that why systems such as 2-methylprop-1-ene, where I believe steric ...
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0answers
14 views

Acidity order in substituted Phenylboric acid

Here, we are asked to find the acidity order. For the first one, the answer given is ii > i > iii (c) and for the second one, it is iii > ii > i (b). Any logic that I think for one of ...
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1answer
91 views

Priority of the stabilising factors of resonating structures of Organic compounds

When finding the stability order of resonationg structures of certain molecules.. there is some confusion since some structures satisfy certain factors and others satisfy certain other factors. I want ...
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0answers
76 views

Is N--O--N known to exist?

Commonly, the empirical formula $\ce{N2O}$ refers to the molecule with structure $\ce{N\bond{~--}N\bond{~-}O}$. Is the isomer $\ce{N-O-N}$ known to exist? I'm guessing it is significantly less stable ...
2
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1answer
401 views

How can I know which molecule is more stable when bond order it's equal?

So, I was wondering, I have these molecules $\ce{O^+2}$, $\ce{O^-2}$, $\ce{O2}$ and $\ce{C^+2}$. When I try to find their bond order and their magnetic nature I get this: $\ce{O^+2} = \frac{1}{2} \...
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0answers
31 views

Which is more reactive in E1, benzyl or allyl

I'm don't know the english terminology for chemistry so sorry for probably butchering some terms. My question is, which of these is more reactive in an E1 reaction: The bottom two are the ...
44
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3answers
21k views

What is the reason for the exceptional stability of the cyclopropylmethyl carbocation?

Can someone explain this to me by drawing resonance structures for the cyclopropylmethyl carbocation please? Also one more question, is the tricyclopropylmethyl carbocation more stable than tropylium ...
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1answer
1k views

Compare stability of transition metal cations in aqueous solution

I have to compare the stability of the following transition metal cations: $\ce{Co^3+, Fe^3+, Cr^3+, Sc^3+}$ in aqueous solution. (Source: Joint Entrance Exam (JEE) 2013 Mains India) The first thing ...
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0answers
630 views

How does cross-conjugation destabilizes a molecule?

Wikipedia article on ortho effect suggests that o-toluic acid is more acidic than benzoic acid. This fact is rationalized by suggesting that steric effect causes COOH group to "twist" out of ...
2
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1answer
77 views

Stability of pyridine derivatives

Arrange the following pyridine derivatives in the order of increasing stability of adduct formed with $\ce{BBr3}.$ Explain briefly. I'm pretty confused about which structure is the most stable. I'd ...
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3answers
1k views

Which is the most stable out of the following linked cyclohexadienes?

I am unable to find the answer to this question. I was guessing it should be (2) due to symmetry but my book says it is (3) without any explanation. I know that stability is determined by how low the ...
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2answers
7k views

Which of the following carbanion is most stable?

The carbanion which is most stable is The answer is 1. But why won't the answer be 2 because it shows resonance, whereas 1 only shows I effect and resonance effect is more dominant?
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1answer
3k views

Thermal stability of interhalogen compounds

I am striving over the question that what would be the stability order of the following interhalogen compounds : $\ce{ClF3, BrF3}$ and $\ce{IF3}$. One probable answer I got is that stability of ...
4
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3answers
5k views

How is sulphur trioxide formed and why is it stable? [duplicate]

Structure of $\ce{SO3}$ (sulfur trioxide): In the molecule, if each oxygen atom shares two electrons with sulfur atom then how does the sulfur atom remain stable? It already has 6 valence electrons ...
10
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1answer
327 views

Were gold(II) complexes synthesized for the first time in 2017?

Recently in the Google news feed, I discovered this news: Gold stabilized in very rare oxidation state +II Missing golden link found: Divalent gold complex isolated for the first time in a ...
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2answers
2k views

Ring expansion from a given cyclic carbocation

How will the cyclobutane ring behave in the case of cyclobutylmethylium (cyclobutylmethyl cation)? I initially thought there would be ring expansion to a five membered ring so that there may be less ...
10
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2answers
1k views

Can a six member ring expand to achieve octet completion to stabilize a carbocation?

(Probably unnecessary background: I came up with this carbocation while predicting the major product of $\ce{NaNO2/HCl}$ with 1-(methylamine)cyclohexan-1-ol) Will the following carbocation ...
2
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1answer
424 views

Performing an SN1 reaction in a polar aprotic solvent

Straightforward question What would be the outcome of having an SN1 reaction carried out in a polar aprotic solvent? I have found this question approached scarcely and with unsatisfactory answers. ...
0
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1answer
53 views

Why isn't just a fully occupied valence s orbital stable?

Why arent elements like calcium with an electron configuration of $[\text{noble gas}]\ n\mathrm{s}^2$ stable, although all the populated orbitals are fuully filled? Why is it necessary to obtain an ...
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0answers
64 views

Hydrogen isotope effect on methyl shift

Consider this typical 1,2 methanide shift in a carbocation: Which isotopic form of methanide ($\ce{CH3, CD3, or CT3}$) would migrate from secondary carbocation to form more stable tertiary ...
2
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2answers
1k views

How to figure out the most stable conformation of the diastereomer?

Question 1: Which of the following Newman projections represent the most stable confirmation of the diastereomer of the molecule given below? I guess my main question is looking only at the Newman ...
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2answers
26k views

Carbocation stability order

I was wondering whether the following order (from here) is correct: In the first inequality, why did 9 hyperconjugations dominated resonance effect of benzene ring? In the last inequality doesn't ...
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0answers
30 views

Comparing stability of CF3+ and CD3+ [duplicate]

This is a question from my text book. Compare the stability of carbocation between $\ce{CF3^+}$ and $\ce{CD3+}$. The answer is given $\ce{CF3+}$ due to backbonding. But I see backbonding as a sort ...
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0answers
83 views

Does 2‐indanone form a stable hydrate?

Following up the question Formation of a stable hydrate. I understand that for cyclopropanone the change in hybridization is the reason for stabilization of hydrate since it relieves the angle strain. ...
2
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3answers
186 views

Why is 1,2,3,4,5,8-hexahydronaphthalene more stable than 1,4,4a,5,8,8a-hexahydronaphthalene? [closed]

Why is 1,2,3,4,5,8-hexahydronaphthalene (1) more stable than 1,4,4a,5,8,8a-hexahydronaphthalene (2)? A follow-up question is about stability being estimated by counting the α-hydrogens. In the first ...
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1answer
143 views

Comparing stability of 2-propenyl cation and 1-propyl cation

Compare the stability of 2-propenyl cation and 1-propyl cation: $$\underset{\text{2-propenyl cation}}{\ce{CH2=CH-CH2+}}\qquad \underset{\text{1-propyl cation}}{\ce{CH3-CH2-CH2+}}$$ In 2-propenyl ...
4
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3answers
239 views

Stability of α-chlorocarbocations

I'm trying to compare the relative stability of two carbocations: $$\ce{CH3-\overset{+}{C}H-Cl}\quad\text{vs}\quad\ce{CH3-\overset{+}{C}H2}$$ Does the $\ce{Cl}$ exert a +M effect to stabilise the ...
2
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1answer
282 views

Comparing the stability of geminal diols [duplicate]

Arrange the given gemdiols in decreasing order of their stability: I thought that high angle strain would correspond to low stability, and therefore I compared the stability of the rings, which ...
2
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0answers
124 views

Why does more s-character stabilise Carbanions?

Since carbanions carry a negative charge, more the distribution of electron density, more is the stability. What does this have to do with more s character? Does the distribution of electron density ...
3
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2answers
121 views

Method of deriving some properties or possible method of synthesis of a specific monomer

This is kind of like two questions but since they're related I have put them together. Consider a monomer under a hopefully anatomically correct name 'Phenyl Carbolithia Divinylene Oxide [$\ce{...

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