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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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2answers
47 views

Which Carbocation is most stable among the three? [on hold]

According to me the answer should be (C) as that Carbocation will be stablized by resonance with Chlorine. I have read that resonance is the biggest deciding factor about the stability of a ...
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0answers
21 views

Why is [Cu(NH3)6]2+ unstable? [duplicate]

why does it convert to $$ [Cu(NH3)_{4}(H2O)_2]^{2+}? $$
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1answer
32 views

Why does charge separation decrease stability of resonances forms?

Why is an resonance form with negative and positive formal charges in its atoms, lets say +1 and -1, less stable than an resonance form with just positive or negative formal charges, lets say just +1 ...
1
vote
1answer
33 views

Stability of formyl chloride

Why is formyl chloride unstable? I know it is just a combination of CO and HCl. But why it is unstable whereas other acyl chlorides are stable, like acetyl chloride?
0
votes
1answer
37 views

Stability of tertiary carbocation [duplicate]

Our teacher told us that a carbocation connected to 3 cyclopropane rings is among the most stable carbocations. But I am unable to understand how, as resonance (the most important factor governing ...
0
votes
1answer
49 views

Stability of alkene

Sorry for this silly doubt but why is CR2=CH2 alkene more stable than CHR=CHR alkene? Both have same number of alpha hydrogens. I thought that the latter is more stable as in its trans isomer, the R ...
2
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0answers
43 views

Could Be2- exist?

I understand that Be2 cannot exist, since it has as many electrons in the antibonding as in the bonding orbitals. But it seems to me that since the next electron would go into the πu orbital, which ...
0
votes
1answer
46 views

Thermodynamic stability and Inertness [duplicate]

The following is from my teacher's notes: The reaction (where the reaction mixture is thermodynamically unstable but kinetically inert) tends to go as indicated by a positive total entropy change, ...
1
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1answer
70 views

Which has more enol content?

According to me, resonance in {a} is more effective than {b}. And for monocyclic ketones, enol has very less content. I say {1} has lesser enol than {2}. Which is right?
4
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3answers
104 views

Is there a thermodynamic driving force for racemisation?

Why does racemisation occur? My doubts are: Is it due to entropy? If it is due to entropy, how is the reduction of optical activity by racemisation a consequence of increased thermodynamic ...
0
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1answer
199 views

According to MO theory, why is $\ce{Li2+}$ more stable than $\ce{Li2-}$?

By MO theory, $\ce{Li2}$ fill up two electrons in $\sigma_{g2s}$ molecular orbital. $\ce{Li2+}$ fill up one electron in $\sigma_{g2s}$ MO. $\ce{Li2-}$ fill up two electrons in $\sigma_{g2s}$ MO, and ...
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1answer
50 views

Resonance structure and stability

Does the existence of resonance structures always translate as stability? I've been taught that resonance structures generally "spread out" charge in order to compensate for deficiency or excess of ...
3
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0answers
77 views

Comparing thermal stabilities of MgCl2 and BaCl2

I read that to compare thermal stabilities of ionic solids: if the solid has a monoatomic anion, we compare thermal stability on the basis of lattice energy which is inversely proportional to size. ...
3
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1answer
44 views

Instability due to neutrons

Why does an excess of neutrons leads to instability? For example, both $\ce{^{3}H}$ and $\ce{^{4}H}$ are unstable, with respective half-lives of $3.89\cdot 10^8$ and $1.39\cdot 10^{-22}$ seconds. ...
0
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0answers
66 views

Why is ninhydrin stable as a geminal diol? [duplicate]

The following image depicts the structure of ninhydrin - $\ce{C9H6O4}$ Ninhydrin, as you see has two hydroxyl group attached to same carbon. In general, geminal diol (or gem-diol, for short) are ...
2
votes
1answer
95 views

Why doesn't cyclopropyl methyl carbocation stabilises itself by ring expansion? [duplicate]

I have been taught that ring expansion stabilises smaller cyclic compounds to a great extent. So why does cyclopropyl methyl carbocation shows such type of resonance rather than expanding its ring ...
0
votes
1answer
47 views

Ring Expamsion And Final Structure

[IF you don't like to read the question just look at the 3 pictures the first one have carbocation which have to be stablised by ring expansions the other 2 are my predicted structure so please ...
2
votes
2answers
238 views

Stability of geometrical isomers in cycloalkanes

Among the following, which should be the most stable compound? 1)Cis-cyclohexane-1,2-diol 2)Trans-cyclohexane-1,2-diol 3)Cis-cyclohexane-1,3-diol 4)Trans-cyclohexane-1,3-diol My thought process is-...
6
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1answer
304 views

Why can't NH5 form?

In ammonia a nitrogen atom forms 3 covalent bonds with hydrogen atoms and has one lone pair which can be used in a dative covalent bond with another hydrogen atom to form an ammonium ion. Instead of ...
13
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1answer
142 views

Stability of keto-enol vs. conjugation

I am trying to figure out which tautomer of creatinine: is more stable. We see that the enol tautomer is more highly conjugated: the $\pi$ electrons from the alcohol to the double bond to the $\pi$ ...
2
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0answers
151 views

What is the most stable structure amongst the keto-enol tautomers of pentane-2,4-dione?

I was assigned the following question and I cannot decide which is the correct answer. Which is the most stable structure? (a) pentane-2,4-dione (b) 4-hydroxypent-4-en-2-one (c) (Z)-4-...
9
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2answers
143 views

Are such high oxidation states as reported by Vojovodic et al. possible?

I am a student in theoretical chemistry and I am confused about the paper: Trends in adsorption of electrocatalytic water splitting intermediates on cubic $\ce{ABO3}$ oxides (Montoya, J. H.; Doyle, A. ...
2
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2answers
179 views

Why is dipositive dilithium more stable than neutral dilithium? [closed]

According to J.D Lee, compounds with fraction bond number are unstable. I calculated that the bond order of $\ce{Li2^2+}$ is 0.5 while that of $\ce{Li2}$ is 1. Hence, $\ce{Li2^2+}$ must be less stable ...
2
votes
1answer
135 views

Why are long oxygen chains unstable? [duplicate]

H-O-H (water), H-O-O-H (hydrogen peroxide), H-O-O-O-H, H-O-O-O-O-H, etc. This is analogous to hydrocarbon chains, methane, ethane, propane, butane, etc. Note the Hydroxygen Chains satisfy 2 covalent ...
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0answers
143 views

Bredt's rule applied to fused bicyclic systems

Ultimate question: Is Bredt's rule equally valid for fused bicyclic system (no bridgehead alkenes without a ring 8 carbons or more), but for other reasons (historical?) it is only defined as applying ...
0
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0answers
8 views

where to find data on thermal decomposition of polysaccharide in aqeuous solution

This is a follow up of my previous question: "effect of over-pressure on lowering viscosity of polysaccharide solution" I would like to know where to find data on thermal decomposition of ...
0
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0answers
304 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
16 views

Rate of hydrogenation for alkenes [duplicate]

Which of the two alkene will react fastest with $\ce{H2}$ under catalytic condition? I know that rate is inversely proportional to the stability of alkene but here which will be more stable. ...
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votes
2answers
60 views

How two neutral atoms are together with no force between [duplicate]

How sodium atoms exist together when they all have unstability due to an extra electron present in their outermost shell? I mean how two neutral atoms Na atoms are existing together in form of white ...
7
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2answers
186 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 ...
0
votes
1answer
70 views

Effect of halogen atom on Markovnikov's rule

I know that the Markovnikov's rule is because of the stability of carbocations. If a halogen atom (electron-withdrawing group) is directly attached to the carbon atom carrying a positive charge, would ...
0
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0answers
78 views

Reaction of pentadiene with HBr

$\ce{H2C=CH-CH=CH-CH3}$ reacts with $\ce{HBr}$ at low temperature. What would be the product? At low temperature, product would be kinetic and less stable, while the carbocation intermediate would ...
14
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2answers
2k views

Why is cis-1,2-dichloroethene more stable than trans-1,2-dichloroethene?

Why is cis-1,2-dichloroethene more stable than trans-1,2-dichloroethene? Usually, trans compunds are more stable than cis ones, due to less strain and its non-polarity. But, in this case it's quite ...
0
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1answer
374 views

Stability comparison of benzylic carbocation and benzene

Which is more stable - benzylic carbocation or benzene - and why? Benzylic carbocation may have more resonance structure, but these structures are destroying its aromaticity as well. So, how do we ...
4
votes
4answers
515 views

Why do chromyl bromide and chromyl iodide not exist?

It is known that chromyl chloride exists (popularly known as the product of a test for presence of chloride ion) but chromyl bromide and chromyl iodide are unknown. Why is it so? Why don't they exist?...
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2answers
196 views

Can an organic compound undergo ring contraction to give more stable carbocation? [duplicate]

Throughout my journey in organic chemistry I’ve only seen ring expansions by a compound in order to attain more stability, but yesterday I thought about the following reaction. I feel that ring ...
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0answers
110 views

What is the stability order for these octahydrobiphenylene structures?

According to me most stable is Z because it has maximum alpha hydrogen, Between X and Y both have same alpha hydrogen, but X has conjugation. So it is more stable than Y. So Order is Z>X>Y. Is my ...
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1answer
143 views

Why does fluorine form stable oxides while chlorine form unstable oxides? [closed]

The fluorine however it says my text book doesn't combine well with oxygen, nitrogen and itself but when about its oxides they are quite stable as $\ce{O3F2}$ has a melting point of $\pu{363 °C}$ ...
7
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2answers
436 views

Why does formaldehyde exist primarily as the gem-diol in aqueous solution?

From Wikipedia, Methanediol is the product of the hydration of formaldehyde $\ce{H2C=O}$, and predominates in water solution: the equilibrium constant being about $10^3$ and in a 5% by weight ...
4
votes
3answers
980 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 ...
0
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0answers
366 views

Why are alkyl groups more electron donating than hydrogens?

We are taught that alkyl groups are electron donating because they have a partial negative charge from the hydrogen, due to the electronegativity difference, and this can transfer over to a ...
0
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0answers
276 views

Why is carbonic acid unstable? [duplicate]

Carbonic acid decomposes to form carbon dioxide and water. Why does this happen? I asked my teacher and he said that while carbonic acid has two hydroxyl $\ce{OH}$ groups on the same carbon which ...
2
votes
1answer
786 views

Rank the following radicals in order of decreasing stability

Question Rank the following radicals in order of decreasing stability Aromaticity makes a cyclic compund more stable. Here, 1 and 3 are aromatic since they follow Huckels rule(Or am I wrong ...
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vote
0answers
44 views

Do amides oxidize to double-bonds?

Do amides from primary or secondary amines ever oxidize to a double-bond on the nitrogen? For example, like from an $\mathrm{R \bbox[yellow]{\color{red}{-}}(NH)-(C=O)-R'}$ to an $\mathrm{ R \bbox[...
4
votes
1answer
177 views

Why is ordinary soap and water adequate to decontaminate possible nerve agents?

In the news it was announced that anyone who might have been exposed in the recent Salisbury nerve agent incident should wash any potentially contaminated clothing as normal using regular detergent ...
0
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0answers
68 views

Among [PCl4]+ and [PCl4]- which is more thermodynamically stable?

According to my textbook, in $\ce{[PCl4]+}$ phosphorus exists in +5 state and in $\ce{[PCl4]-}$ phosphorus exists in +3 state. Which of these ions is more stable in terms of standard enthalpy of ...
5
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0answers
129 views

pKa of different sites of butanone

From what I can tell, deprotonation of the central hydrogen leads to the more thermodynamically stable product (most substituted double bond. i.e. most stabilization by hyperconjugation). Therefore, ...
3
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2answers
292 views

Thermodynamic stability of benzene derivatives

Q1. How can we comment on the thermodynamic stability of the following benzene derivatives? Q2. What does thermodynamic stability mean, in general? What does it mean to compare the thermodynamic ...
2
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3answers
2k views

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 > ...
4
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1answer
262 views

What drives a molecule/atom towards stability? [duplicate]

I'm very familiar with the concept that chemical reactions occur because the reactants a state of stability via the reaction. It's a very satisfying and fulfilling statement. But my question has ...