Questions tagged [organic-chemistry]
Use this tag for questions relating to organic molecules and their properties (structure of organic molecules, spectroscopic properties, reaction mechanisms, stereochemistry etc). DO NOT use this tag as the only tag in your question, as this tag by itself cannot appropriately classify your question. Always use this tag in addition to other more specific tags.
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Is there a general consensus on the causes of the alpha-effect?
There have been various explanations posited for the α-effect. The α-effect refers to a phenomenon wherein nucleophiles with lone pairs on atoms adjacent (i.e., in the α- position) to the atom bearing ...
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Ortho-effect in substituted aromatic acids and bases
When comparing o,m,p-toluidine basicities, the ortho effect is believed to explain why o-toluidine is weaker. But when comparing o,m,p-toluic acid basicities, the ortho effect is stated as a reason ...
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How do people know HCN smells like almonds?
I was told by my chemistry teacher that $\ce{HCN}$ smells like almonds. She then went on to tell a story about how some of her students tried to play a prank on her by pouring almond extract down the ...
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How do organic chemistry mechanisms become accepted?
Now I have been learning chemistry for five years. I remember when I started organic chemistry, it was fun to draw arrows between molecules to show, as if in a mathematical demonstration, how the ...
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Is carbon dioxide organic or inorganic?
Today in chemistry class we were discussing Organic Chemistry. We discussed what organic compounds basically are and then I asked the teacher whether $\ce{CO_2}$ is organic or not. She told that it is ...
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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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Regioselectivity of acid-catalyzed ring-opening of epoxides
Not to be confused with what is the mechanism of acid-catalyzed ring opening of epoxides.
What is the correct order of regioselectivity of acid-catalyzed ring-opening of epoxides: $3^\circ$ > $2^\...
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Why does nitration of N,N-dimethylaniline occur at the meta position?
The nitration of N,N-dimethylaniline with $\ce{H2SO4}$ and $\ce{HNO3}$ gives mainly the meta product, even though $\ce{-NMe2}$ is an ortho,para-directing group. Why is this so?
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Is buckminsterfullerene aromatic?
According to Wikipedia,
The $\ce{C60}$ molecule is extremely stable,[26] withstanding high temperatures and high pressures. The exposed surface of the structure can selectively react with other ...
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Mechanism of arene side chain oxidation by permanganate
When treated with hot, concentrated acidic $\ce{KMnO4}$, arenes are oxidised to the corresponding carboxylic acids. For example, toluene is oxidised to benzoic acid.
I've tried to examine how this ...
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Why does cyclopropane react with bromine?
In my exam, I was asked why cyclopropane could decolourise bromine water (indicating that it reacted with the bromine).
All I could guess was that it is related to the high angle strain in ...
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What's the biggest organic molecule that could have a smell?
For a molecule to have a smell it's necessary that the molecule be volatile enough to be in the air. So I think that excludes molecules which are solid at room temperature and atmospheric pressure. ...
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Inductive effect of hydrogen isotopes
Why does the electron-donating inductive effect (+I) of the isotopes of hydrogen decrease in the order $\ce{T} > \ce{D} > \ce{H}$?
(where T is Tritium and D is Deuterium)
Google has nothing to ...
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Do molecules with bridges through rings exist?
Do molecules with bridges through rings (in a manner illustrated by this) exist?
I sometimes get results like this when doing Energy Minimization on molview.org. For example:
Is this actually a ...
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How can carbon dioxide be converted into carbon and oxygen?
How can $\ce{CO2}$ be converted into carbon and oxygen?
$$\ce{CO2 -> C + O2}$$
Alternatively:
$$\ce{CO2 + ? -> C + O2}$$
I'm aware that plants are capable of transforming $\ce{CO2 + H2O}$ to ...
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Why does alcoholic KOH prefer elimination whereas aqueous KOH prefers substitution?
What is the basic difference between aqueous and alcoholic $\ce{KOH}$? Why does alcoholic $\ce{KOH}$ prefer elimination whereas aqueous $\ce{KOH}$ prefers substitution?
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Differences between phenols and alcohols
I know phenols are more acidic as compared to alcohols, but are they considered different from alcohols?
Sure, you can study something as a subset, but are phenols considered a subset of alcohols, or ...
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In what way could benzoin give Tollen's test?
In Q29 of Joint Entrance Exam (JEE) 2016 India, the official answer key mentions that benzoin gives Tollen's test. However, I saw this post which says that it doesn't: Why do α-hydroxy ketones give ...
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Why do SN1 and SN2 reactions not occur at sp2 centres?
I was told in my organic chemistry course that $\text{S}_\text{N}1$ and $\text{S}_\text{N}2$ reactions did not occur at $\text{sp}^2$ centres. When I asked why, I was not given a satisfactory ...
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Five-pointed crown alkane C25H40: does it exist?
My 4 year old granddaughter, playing with molecular models, began making a cyclopentane ring, each of whose carbons bore a spiro-connected cyclopentane ring of its own , in the manner of spiro[4.4]...
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Is Hexafluorocyclohexane the "Most Polar" Small Molecule?
Earlier this year, there was a lot of attention when all-cis 1,2,3,4,5,6-hexafluorocyclohexane was synthesized*:
Notably, C&E News quoted the lead author:
This compound is remarkable for being ...
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IUPAC nomenclature: "Smallest sum of locants"?
While naming any compound, the numbering should be done such that position of substituted groups gives smallest sum.
I'm struggling with the IUPAC naming for cyclic compounds. How exactly does this ...
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Why is pyrimidine less basic than pyridine?
From Wikipedia's article on pyrimidine:
Because of the decreased basicity compared to pyridine, electrophilic substitution of pyrimidine is less facile.
But why is pyrimidine less basic than ...
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What is a non-classical carbocation?
What is a non-classical carbocation?
How is it different from a classical carbocation?
I am confused as I have come across this term many times on Chem.SE but there seems to be nothing for my level ...
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Is pyrene aromatic despite failing Hückel's rule?
Pyrene doesn't seem to be aromatic. However, sources claim that it is aromatic.
Considerations:
Pyrene is cyclic. ✓
Pyrene is flat (planar). ✓
Pyrene has 16 π electrons.
Every atom in the ring ...
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IUPAC nomenclature for an interesting looking organic compound
How can I name this organic compound while adhering to the IUPAC standards?
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What are the meanings of dotted and wavy lines in structural formulas?
So I came across this diagram,the other day:
As a chemistry student, I am well-versed with the dashed and wedged lines, but I was wondering what the wavy and the dotted line represent?
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Is the ammonium substituent (-NH3+) really meta-directing in electrophilic substitution?
If we make a resonance structure for the anilinium ion, with positive charge at either the ortho or the para position, we get a pentavalent nitrogen, which is not possible. So, how is the $\ce{-NH3+}$ ...
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Chemistry behind Gale's coffee maker in Breaking Bad
Is there a scientific basis for the coffee making equipment which Gale Boetticher describes in Breaking Bad?
He talks about maintaining the right conditions for bringing out the coffee flavor without ...
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Acidity of substituted phenols
Phenol has a $\mathrm pK_\mathrm a$ approximately equal to $9.9$.
When one studies the acidity of chlorophenols, one notices the following:
First of all, chlorophenols are more acidic than phenol, ...
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Why is methanol toxic?
There are two points of view for the answer of this question:
The biological view, the only one that I faced during my research, states that since it can trigger perilous conditions like metabolic ...
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Unusual Friedel–Crafts alkylation with pivaloyl chloride
In class we were told of an anomalous Friedel–Crafts reaction with a tertiary acid chloride — $\ce{(CH3)3CCOCl}$, or pivaloyl chloride. When this reacts with benzene in the presence of $\ce{AlCl3}$, ...
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Why can't Pd/C and H2 reduce both the alkene and carbonyl portions of α,β-unsaturated carbonyls?
Why is it that the major product of the reduction of chalcones the ketone and not the monoalcohol? In other words, Why isn't the major product a benzyl alcohol?
From what I understand, catalytic ...
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What's the difference between a nucleophile and a base?
Obviously it depends on the context whether you would call a particular species a nucleophile or a base but are the two terms largely synonymous or is there a difference?
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What is the role of pH in azo coupling reaction of diazonium with phenol and aniline?
Why is it so that azo coupling with phenol needs basic pH (9–10) and with aniline it needs acidic pH (4–5). How does pH participate in the mechanism? I have searched the internet for quite a while ...
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Stereoselectivity of dihydroxylation with osmium tetroxide
Dihydroxylation responds to steric effects and proceeds at less hindered positions. What will be the major product in the following reaction if the reagent used is $\ce{OsO4}$ followed by $\ce{NaHSO3}$...
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Why is '-ethane' in 'methane'?
Is there a chemical or historical significance in the fact that 'ethane' is just 'methane' without the 'm'?
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Why is 1-ethylidene-4-methylcyclohexane chiral?
As far as I can tell, there doesn't seem to be a chiral carbon in the compound, 1-ethylidene-4-methylcyclohexane. The C-4 of the cyclohexane ring has two groups with exactly the same connectivity, and ...
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How do I extract cyanide from apple seeds?
I'm working on a crime story about cyanide poisoning from apple seeds. I just would like to have an idea of what processes and extraction techniques might be involved in getting cyanide from the seeds....
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Sp5 hybridization in cyclopropane?
I have never before heard/read about something as a $sp^5$ hybridization. Today, Henry Rzepa's blog post made me aware of the existance of such a bonding system. That made me search a little bit and I ...
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Explanation for the trends in nucleophilicity—Orbital interactions or electrostatic attraction
The trend of halide nucleophilicity in polar protic solvents is $$\ce{I- > Br- > Cl- > F-}$$
The reasons given by Solomons and Fryhle[1], and by Wade[2] are basically as follows.
Smaller ...
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Relative stability of cis and trans cycloalkenes
Why is the stability of (Z)-cyclodecene 2 greater than that of (E)-cyclodecene 1?
I'd think that since 1 contains a trans double bond instead of a cis double bond, it should experience less steric ...
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Why does hyperconjugation help for ring cleavage?
The question was to rationalize it the ring cleavage happens concerted or non-concerted.
The papers "The Mechanism of the Thermal Decomposition of
1-Pyrazolines and Its Relationship to
...
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Selective nitro reduction of poly nitro compounds
Is there any way through which I could selectively reduce one $\ce{NO2}$ group from a dinitro- or trinitro- compound to an amine.
I was reading Solomons and Frhyle and it says that m-dinitrobenzene ...
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Why does the unstabilised Wittig reaction selectively form cis alkenes?
This question is meant for a simple unstabilised ylide.
The mechanism of the Wittig reaction, as given on ChemTube3d, involves a concerted formation of the oxaphosphetane (this is generally favoured ...
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Why does chocolate melt so easily?
(Yes, I know the question sounds super-trivial... but bear with me here)
Most chocolates (especially milk-chocolate) tend to melt into this sticky (albeit delicious) mess at temperatures slightly ...
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Why are DCM and chloroform so resistant towards nucleophilic substitution?
In the book Organic Chemistry by J. Clayden, N. Greeves, S. Warren, and P. Wothers I found the following reasoning:
You may have wondered why it is that, while methyl chloride (chloromethane) is a ...
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Is activated carbon classified as organic or inorganic?
Organic compounds are typically defined as “molecules containing carbon”. Wikipedia states that there for some historical (read: non-logical) reasons,
a few types of carbon-containing compounds ...
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Which carbocation is more stable, the ethyl- or 1-propyl-carbocation?
$\ce{C2H5+ vs \ C3H7+}$
There are two conflicting trends here.
Inductive effect of ethyl will be higher than that of methyl so carbocation attached to ethyl (3 carbons in total) should be more stable....
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Why are tertiary carbocations the most reactive, if they're already stable?
This may seem silly, but doesn't it seem weird for a compound that's stable (in this context, the tertiary carbocation) to be the most reactive?
I mean, wouldn't it be the least, given that it's ...
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