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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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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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 ...
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22 views

Meaning Of Increasing Successive Stepwise Stability Constant

What does it mean if the successive stepwise stability constant increases rather than decreases during the formation of complex ions? Does this simply mean that the final complex is the most stable, ...
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48 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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1answer
48 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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20 views

Existence of gem-diols [duplicate]

In the mechanism for Reimer-Tiemann's reaction, I was told that two alcohol substituents on the same carbon atom are unstable, and this is why salicylaldehyde is formed. In fact, this is not the first ...
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1answer
142 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. ...
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1answer
48 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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47 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 ...
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28 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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59 views

Major product from allylic halogenation of alkenes

Allylic halogenation of butene happens in the following way: The RDS of this radical chain mechanism is allylic hydrogen abstraction ($\ce{H_a}$) from the allylic position to give a 1° allylic ...
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68 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. ...
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1answer
114 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 ...
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2answers
64 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 ...
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3answers
169 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
94 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 ...
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52 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 ...
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1answer
51 views

More Anti-bonding or less bonding electrons?

Is a molecule more stable with less bonding electrons or more anti-bonding electrons? This question arose when I was asked the stability comparison between $\ce{N2^+}$ and $\ce{N2^-}$.
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57 views

Adding a base and a salt to a hydrated complex

The question goes like this: $\ce{Fe(NO3)3}$ V= $\pu{1 liter}$ and $\ce{[Fe(NO3)3]} =\pu{0.1 moles/liter}$. Calculate the $\mathrm{pH}$ of this solution using the values of $K$ given. We add a solid ...
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43 views

Has mercury(II) cyanate ever isolated as a free compound?

Recently, I have answered a question "Comparing explosive properties of mercury(II) cyanate and mercury(II) fulminate" where stability of cyanate vs fulminate was discussed. While I was ...
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2answers
166 views

Order of rate of acid catalysed dehydration of alcohols

The relative rate of acid catalysed dehydration of following alcohols would be: According to me, we have to arrange them in order of their carbocation stability. Q will be the most stable as it is ...
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1answer
129 views

Comparison of carbocation stability in bicyclo compounds

Question Which is the most stable carbocation ? Answer My attempt I answered as 1 as the first one had +M of -O- and hyperconjugation effect as the positive charge is at para position. Why is the ...
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1answer
121 views

Reaction of styrene oxide with hydrogen iodide

The question is to find the product of the reaction of Styrene Oxide with Hydrogen Iodide. According to me, this should be the mechanism- As the benzylic carbocation will be more stable, therefore ...
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52 views

Stability of free radicals [closed]

If given a question to compare stability of free radicals, can we always check it by same parameters that we use for stability of cations (since both are electron deficient) or is there any exception ...
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2answers
171 views

Rate of dehydration of alcohols having keto group

The following question was asked in IITJEE-Screening 2000, Which of the following will be most readily dehydrated in acidic conditions? I thought that the answer would simply be (c), as its ...
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1answer
253 views

Stability of carbocations with -M groups in beta position

First part The original question was to arrange the following compounds in the order of their rate of dehydration with conc. $\ce{H2SO4}$:- (A) $\ce{CH3-CH(OH)-CH2-CH=O}$ (B) $\ce{CH3-CH(OH)-CH2-C(=O)...
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1answer
168 views

Rate of dehydration for butan-2-ol and butane-2,3-diol

A question taken from a test series (Vibrant, India): Amongst butan-2-ol and butane-2,3-diol, which has higher rate of dehydration? The carbocation formed in butane-2,3-diol is more stable as it ...
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43 views

Reactivity comparison between benzaldehyde and acetaldehyde [duplicate]

One of my teacher says that $\ce{Ph-CHO}$ is more reactive than $\ce{CH3-CHO}$ in performing nucleophillic addition reaction because $\ce{—Ph}$ is planar and thus offers less steric hindrance as ...
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42 views

Stability of radicals

I recently came across a question about the stability of radicals and this option was given as correct. $\ce {F2C^.H}>\ce {C^.H3} $ And the solution was given that $\ce{FC^.H2}$ and $\ce{F2CH^.}$...
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1answer
142 views

Comparing heat of hydrogenation among 1‐methylcycloprop‐1‐ene, 3‐methylcycloprop‐1‐ene and methylenecyclopropane

Problem Which of the following orders is correct for heat of hydrogenation of these compounds? A) 1 > 3 > 2 B) 3 > 2 > 1 C) 3 > 1 > 2 D) 2 > 1 > 3 Answer My Attempt Heat of ...
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1answer
146 views

Stability of dialkyl substituted alkenes

The stability order of alkyl substituted alkenes with respect to heat of hydrogenation was given as $$\ce{R_2C=CH2} > \ce{RHC=CHR}~(\textit{trans}) > \ce{RHC=CHR}~(\textit{cis}).$$ While I ...
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2answers
289 views

Stability of F- Cl- Br- I-? In aqueous state [closed]

If we talk about hydrolysis F- will be more heavily hydrolysed so it should be more stable in aqueous state. But I know that HI is a stronger acid than HF. So the stability of conjugate acid ie I- ...
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1answer
37 views

Why are bonded ions more stable than separate ions? [closed]

I was reading on the Born-Haber cycle when I encountered a problem. The textbook seemed to suggest that since energy must be supplied to separate an ionic compound into it's composite ions, then the ...
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3answers
218 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 ...
4
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1answer
273 views

Newman projections: how to tell which groups are bulkiest to determine what is the most stable conformation?

The scenario Let's say we have a molecule where in the Newman projection the front carbon has a hydrogen, methyl and an ethyl, and in the back carbon there's a hydrogen, something like a S, Cl or Br (...
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1answer
246 views

Stability of CI4 and PbI4

I have read in my textbook that $\ce{CI4}$ is more stable than $\ce{PbI4}$ due to inert pair effect. But shouldn't we also consider the effect of steric repulsions? In $\ce{CI4}$, four large iodine ...
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2answers
67 views

Ortho effect in cyclohexane

Compare the acidities and basicities of the compounds in the first and second row respectively. In aromatic compounds the methyl group would cause an "ortho" effect. Here we don't have an aromatic ...
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1answer
47 views

Energy lost due to stability [closed]

We used to say that when an atom is stable it is in its minimum energy state.Every shell has its fixed energy. So from where does the energy come which is lost by an atom to achieve stability. Do ...
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31 views

Stability of Peroxynitric Acid in cold temperature

I have a question about the stability of Peroxynitric Acid i.e. $\ce{HO2NO2}$ at cold temperature. I know that it becomes stable when temperature decreases, but what is the specific reason for it? I ...
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1answer
147 views

What does it actually mean by stability of an atom

There are several rules related to stability of an atom, like octet rule, half filled or fully filled d orbital etc. But none of them (at my best knowledge) does not explain why an atom is stable when ...
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0answers
83 views

Cis-Trans Isomers Heat of Combustion

Consider the 4 cis-trans isomers for the above compound. In what way would the cis-trans isomers affect their heat of combustion. I think that if the substituents are on alternating sides of the ...
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2answers
94 views

Why is hofmann product prefered here?

In the following reaction, Hofmann elimination is preferred. This reaction takes place by E1 mechanism. I thought the Zaitsev product would be major due to 1 extra hyperconjugating structure. In the ...
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27 views

What explains the stability of aromatic compounds? [duplicate]

We are taught in High school that aromatic compounds are highly stable. Why is that true? Also, Why are Antiaromatic compounds highly unstable? Aromatic compounds have 4n+2 (n is a whole number) ...
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121 views

Stability order of p-quinone, o-quinone and diphenoquinone

Question Determine stability order: Answer Thoughts I found this question quite tricky and confusing. According to my concepts and logic 3 should be non-aromatic, while 1 and 2 are antiaromatic. ...
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2answers
90 views

Which resonance structure would be favorably contributed to the actual structure?

Total number of pairs of resonating structure in which second is more favorable than first: I know (d) and (e) have second structure more stable. (f) has both same. According me to, (a) and (c) ...
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1answer
60 views

Para effects on substituents in aromatic compounds

I wanted to know how to compare the following compounds on basis of acidic strength. I have to find the acidic strength of following compounds with $\mathrm{X}=\ce{CH3, \ OCH3,}$ and $\ce{NO2}$. For ...
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0answers
161 views

Are all ions stable? [closed]

My science teacher says that all ions are stable, which seems wrong to me. For example $\ce{He^{-1}}$ is an unstable ion of helium, and although it might not exist in the real world, it is still ...
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53 views

Why isn't protium nucleus considered most stable nucleus?

My chemistry teacher told me that $\ce{^{56}Fe}$ is the most stable nucleus because of the highest binding energy per nucleon. But if we consider a protium nucleus, it has only 1 proton so there is no ...
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1answer
231 views

Why do stable compounds have a lower heat of combustion?

My brain somehow doesn't accept that more stable compounds require have less enthalpy. Isn't it like, if a compound is stable, it requires more energy to break the bonds because the compound doesn't ...
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3answers
124 views

Odd looking carbocation stability order [duplicate]

I am studying introductory organic chemistry, suddenly this one started looking odd, The carbocation stability for three compounds as given by my book is shown below, Let me call those as ...

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