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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Why are palladium and platinum carbonyls unstable at room temperature?

By palladium and platinum carbonyls, I mean the mononuclear, homoleptic, charge-neutral, binary carbonyl complexes of the form $\ce{M(CO)_n}$ and not any heteroleptic complexes like $\ce{Pd(CO)(PPh3)3}...
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1answer
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Polarity and stability

Why is cis-1,2-cyclohexadiol less polar than trans-1,2-cyclohexadiol? I know it has something to do with stability and chair conformations, but I'm not sure how it relates to polarity. I know cis-1,...
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Hazards of eating non-stick coating, particularly considering the coating primer [closed]

How unhealthy are teflon / non-stick coating chips that end up eaten? What role does the primer coating play? Existing similar threads that don't go into enough detail: 1, 2 I understand that there is ...
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1answer
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why is tertiary carbocation more stable than primary allylic carbocation?

According to general organic chemistry the order of stability is as follows: aromaticity > resonance > hyperconjugation > inductive effect Since primary allylic carbocation shows resonance as well ...
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2answers
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Order of stability of substituted benzyl carbanion

I think the order should be II > III > I. The +m effect should be more in case 1 than in 3, isn't it ? So, 1 should be more unstable than 3. Someone please explain.
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1answer
31 views

Finding the order of decreasing rate of solvolysis of the following molecules with aqueous ethanol [closed]

In this question, I need to find the order of decreasing rate of solvolysis of the above molecules with aqueous ethanol. I think this can be done by finding the species that can form the most stable ...
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2answers
74 views

Carbocation Stability question

Arrange, the following carbocation on increasing order of stability: What have I though is that in second it will be most unstable, as $\ce{-OH}$ group will create most inductive effect (negative), ...
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53 views

Comparing stability of two carbocations [duplicate]

Which of the following ions(A and B respectively) is more stable? How can we explain this on the basis of resonance? Here's what the solution said: Structure (A) is a primary carbocation and has no ...
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Stability of canonical forms [duplicate]

Which of the following ions is more stable? Use resonance to explain your answer. When we have to compare stability of resonance structures we generally check for the following features in the ...
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2answers
119 views

Neutron–proton ratio and isotope stability

I have studied that most of the isotopes (not all of them!) with a neutron–proton ratio of $\ge 1.5$ are unstable; but it is obvious that this is not true in some cases like carbon-14 or technetium-99....
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Is an emulsion of dish soap and vegetable oil stable?

If I fill a glass jar with water, vegetable oil, and dish soap, then mix it until the oil is completely emulsified, will the mixture stay emulsified indefinitely? Assuming the dish soap and oil are ...
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Is it correct to say that benzene is more stable than cylcohexatriene due to delocalization?

I'm virtually all chemistry books I own say that benzene is more stable than the theoretical cyclohexatriene, by 150 kJ to be specific, due to the delocalization of pi electron density around the ring....
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1answer
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How to compare stability between 5‐methylcyclohexa‐1,3‐diene and 3‐methylenecyclohexene?

Problem Compare stability of 1 and 2: Answer My approach Both have the same number of π-bonds. Both have one resonance structure. Both are non-aromatic. In 1 there are three α-hydrogens, whereas ...
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1answer
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Energy of reactants and products [closed]

In some reactions, energy is released and when I want to understand the reason for the release of energy, I find that the energy of the products is lower than that of the reactants. But What is this ...
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Why are sulfoxides usually stable as ylides (S charged positively and O negatively)? What's the BDE for S-O?

I can't find any info on BDE for singularly bonded S to oxygen. Moreover, I'd like to understand, why is it quite usual to find sulfoxides structure written with charge separation?
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Why is PbI₄ not composed of lead(II), iodide and triiodide?

$\ce{Pb^4+}$ is reduced by $\ce{I-},$ so $\ce{PbI4}$ cannot exist with $\ce{Pb}$ in $+4$ oxidation state. But if I replace three $\ce{I-}$ with $\ce{I3-},$ then we can have $\ce{Pb^2+}$ similar to $\...
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1answer
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confusion regarding meta-cresol and phenol

when I googled the answer, i found out that m-cresol has a PKa value of 10.1 whereas phenol has 10.0. I am simply unable to use any logic to compare their strengths. We have been taught only the ...
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2answers
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Why is this compound more basic than the other?

So, the original question was which compound is more basic. Compound A and Compound B respectively. My reasoning is that on protonation, Compound B would be more stable than Compound A as well, ...
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0answers
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Does mercury(II) cyanate exist?

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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4answers
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Reactivity order of electrophilic addition

Find the order of the ease of electrophilic addition of the following: $\ce{H3C-O-CH=CH2}$ $\ce{ F-CH=CH2}$ $\ce{Cl-CH=CH2}$ $\ce{NO2-CH=CH2}$ According to me, it should be 1 > 4 > ...
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1answer
162 views

Ring Expansion And Final Structure

[If you don't like to read the question just look at the 3 pictures; the first one has the carbocation which has to be stabilised by ring expansions. The other 2 are my predicted structure so please ...
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1answer
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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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Why doesn't Sodium (Na) form duplet?

The atomic number of Na is 11 (2, 8, 1). Na loses an electron to achieve octet stability but why can't it just accept an electron to complete duplet stability?
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1answer
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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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1answer
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Stability comparison on the basis of violation of Bredt's rule between bicyclic carbocations

Compare stability between the two bicyclic compounds. Both compounds I and II seem to be unstable because of violation of Bredt’s rule: they are sp2-hybridized. Then how to compare the stability ...
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2answers
237 views

Why and how does ring expansion occur in the dehydration of (cyclobut-3-ene-1,2-diyl)dimethanol?

Can someone explain how does this ring expansion occur with the mechanism? I do understand that the hydride shift occurred because of carbocation stability but why did the ring expand? Can you please ...
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1answer
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Why is the rate of solvolysis of t-butyl chloride lesser than that of 1-chloro-1-methylcyclohexane?

I came across a question regarding relative rate of solvolysis. According to the answer key: My analysis: As in all the three cases, the Cl atom is bounded to a tertiary carbon, hence, all of them ...
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2answers
225 views

Stability of Carbanions

For comparing stability of carbanion, we use the fact that "negative charge is stable on more electronegative atom." So, The stability order is, {electronegative order: $\mathrm{sp \gt sp^2 \...
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1answer
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Heats of combustion of cycloalkane homologues

Heat of combustion increases as the number of carbons increases, but on comparing ethyl cyclopentane, ethyl cyclohexane, andethyl cycloheptane, shouldn't you consider ring stability too? In that ...
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0answers
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What is the relation between strength of a base and the thermal stability of its salts?

In Concise Inorganic Chemistry, $5^{th}$ edition, by JD Lee, while discussing oxides and hydroxides of Group $2$ metals, it has been stated that: The increase in basic strength is illustrated by the ...
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3answers
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Why doesn't H₄O²⁺ exist?

I know this question has been asked previously but I cannot find a satisfactory explanation as to why is it so difficult for $\ce{H4O^2+}$ to exist. There are explanations that it is so because of $+2$...
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1answer
365 views

What does it actually mean by stability of an atom [closed]

There are several rules related to the stability of an atom, like the octet rule, half-filled or fully filled d orbital, etc... But none of them (to the best of my knowledge) explain why an atom is ...
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0answers
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Is bond dissociation enthalpy same for homolytic and heterolytic cleavage? [duplicate]

In David R Klein's Organic Chemistry Book, Chapter of Radicals, one of the 'skillbuilder' questions is to identify the weakest C-H bond in the following molecule: The solution was to split each ...
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27 views

First ionization energy and electron gain enthalpy of dihydrogen / stability comparison of dihydrogen ions [duplicate]

Subset of: How can antibonding orbitals be more antibonding than bonding orbitals are bonding? Stability of $\ce{H2^{-}}<\ce{H2^{+}}<\ce{H2}$ Stability of $\ce{N2^{-}}<\ce{N2^{+}}<\ce{N2}...
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0answers
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Why is salicylic acid less acidic than o- anisic acid? [duplicate]

The Pka of salicylic acid is 2.97 while that of o-anisic acid is 3.73. Why is the latter less acidic if the order of +M effect states that -OH>-OR which should make the conjugate base less stable?
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1answer
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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 ...
2
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1answer
106 views

Why is ethanol more acidic than acetone?

The acidity of a compound is determined by the stability of its conjugate base and the major structure of enolate has a negative charge on the Oxygen atom. Moreover, the negative charge on the O-atom ...
2
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1answer
126 views

Effect of distance on the mesomeric effect

I have always thought that mesomeric effect is somewhat dependent on distance. But I recently came across a question where I was asked to predict the order of stability of o-methoxyphenyl carbocation ...
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1answer
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Why is sulfur hexafluoride more stable than selenium or tellurium hexafluoride?

I was just reading about p Block elements from two different books. Both books say that $\ce{SF6}$ is extremely stable in 16th group due to steric reasons but my question is why is it more stable than ...
2
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1answer
337 views

Stability of iron(III) complexes

Amongst the following the most stable complex is: A) $\ce{[Fe(H2O)6]^3+}$ B) $\ce{[Fe(NH3)6]^3+}$ C) $\ce{[Fe(C2O4)3]^3-}$ D) $\ce{[FeCl6]^3-}$ I know that the answer should be $\ce{[Fe(C2O4)3]^3-},$ ...
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1answer
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Carbocation formation and stability from bromo compounds

When heated,the following bromo-species all form carbocations via $\sigma$ bond cleavage. For each structure draw the corresponding carbocation and briefly describe how it is stabilised. This is my ...
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Preferred radical attack on a polyester

My question concerns the relative stability of a radical next to an ester oxygen compared to a radical next to an ester carbonyl carbon. The stabilizing effect of the electron pairs of ether oxygen ...
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1answer
45 views

What exactly is the idea of gaining stability by the various chemical species?

When we consider the alkaline metals for example, we say that an atom of a metal like sodium gains stability by losing an electron, however this doesn't seem to be a very meaningful statement. Either ...
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1answer
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Variable oxidation state of transition metal ions

Transition metals can form stable ions with different oxidation states. But I am confused why doesn't only the most stable state exist. Let me clarify my question more: $$\ce{Ti^{2+} -> Ti^{3+} + ...
2
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2answers
161 views

Keto-enol tautomerism in a bicyclo compound

Question Which one is more stable- the keto or enol form. The compound given is this: Solution The enol form would violate Bredt's Rule and would therefore be unstable. Hence the keto form is more ...
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1answer
66 views

Acidic character and anion stability across periods and groups of the periodic table [duplicate]

I understand that to compare relative acidity one must consider the stability of the conjugate bases. Across a period the electronegativity of an element increases. And that is for example why $\ce{HF}...
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3answers
2k views

Which tautomer of hexane-2,4-dione is more stable?

Which tautomer will be more stable? Both 1 and 2 show intramolecular hydrogen bonding and form 6 membered cyclic ring, thus increasing the stability. I think I need to compare the effect of the two ...
1
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1answer
213 views

Stability of complexes based on number of rings [duplicate]

$\ce{[Co(edta)]^-}$ has 5 rings in total and in $\ce{[Co(en)_3]^{3+}}$, there are 3 rings. The stability of the former is more than that of the latter. The reason I was told was that a complex with ...
4
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1answer
179 views

Yield of alkyl chloride in the Hunsdiecker reaction

Apparently the yield of alkyl chlorides is low as compared to that of alkyl bromides when preparing alkyl halides using the Hunsdiecker reaction. Why does this occur? The only factor I can see is the ...
3
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1answer
3k views

Stability by using charge/radius rule

I found a question Which is more stable among the following? (a) $\ce{CaCO3}$ (b) $\ce{MgCO3}$ Answer : (a) Explanation was given as: $\ce{Mg^2+}$ has smaller radius than $\ce{Ca^2+}$ and thus ...

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