Questions tagged [physical-organic-chemistry]
For questions about how organic molecules and reactions are investigated using physical experiments.
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Why does wood burn but not sugar?
Fundamentally, they're both carbohydrates, although the cellulose in wood is essentially polymerized glucose, which combined with its isomer fructose forms sucrose.
So why does wood readily burn ...
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Difference between intermediates and transition states
Can someone please explain what exactly the difference between an intermediate and a transition state is?
I understand that they are formed as part of the process in converting the reactants to ...
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What can we say about the dipole moment of terephthalic acid?
The dipole moment of quinol is not zero because it can exist in two different energetically favourable conformations. The weighted average is calculated to arrive a dipole moment of 1.6 D.
According ...
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Out of tropolone and tropone, which is more soluble in water?
According to me tropolone has intramolecular H-bonding, so extent of H-bonding with water will decrease and thus, will be less soluble.
Tropone (Cyclohepta-2,4,6-trien-1-one):
Tropolone (2-...
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Fluorine detection in organic compounds
Many of you will know why I am asking this question. There is a lot of attention recently to the dangers of the so called Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS). In essence organic ...
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How can isotope labelling be used to determine the mechanism of ether cleavage with hydrogen iodide?
When methyl tert-butyl ether (MTBE) is treated with one equivalent of hydrogen iodide, the ether C–O bond is cleaved.
I read that if the oxygen in MTBE is isotopically labelled, it is possible to ...
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Aspirin Hydrolysis at pH 2
Conducting an experiment, I found that very little salicylic acid was evolved performing hydrolysis at $\mathrm{pH \ 2}$ and at $\pu{45 ^\circ C}$. In fact, far more salicylic acid was evolved at $\...
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How do bonds rotate in pericyclic reactions?
In Pericyclic reactions, it is shown that the terminal bonds rotate (conrotation or disrotation) to allow for allignment of the FMO's, thereby forming the sigma bond
However, a detail that most of my ...
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Does π values vary in Hansch-Fujita equations for a given substituent?
I was reading about Hansch-Fujita equations from Hansch-Fujita paramaters and observed that the $π$ values of substituents (analogous to Hammet $σ$ values) change according to the specific environment ...
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How do we obtain the π molecular orbitals for allene via Hückel theory?
For a conjugated system, for instance 1,3-butadiene, we can try to obtain the π molecular orbital energies and wavefunctions via Hückel theory. In our given molecule, there are 4 interacting Pz ...
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Overlap integrals in Hückel theory
In Hückel theory we are only interested in π systems, where $\mathrm p_z$ orbitals overlap. One of the approximations in Hückel theory is that the overlapping $\mathrm p_z$ orbitals are orthonormal:
$...
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Enzyme Kinetics
How come enzymes with a lower $K_\mathrm{m}$ are more easily saturated with substrate than an enzyme with higher $K_\mathrm{m}?$
Is it because enzymes with higher $K_\mathrm{m}$ are able to bind ...
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Vapors of Aqueous solutions
I'm dealing with a common photoresist developer TMAH (tetramethylammonium hydroxide) and attempting to design a vapor sensor for a sealed chamber. Now I havent been able to confirm what exactly is ...
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What exchange timescales are needed to cause decoupling in NMR?
I'll try to explain the source of my confusion as clear as possible:
(*) The methyl protons in toluene are decoupled because the C-C bond between the methyl group and benzene allows very fast ...
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What is the probability the bonds broken with sunlight reforming back?
The maximum wavelength $\lambda$ capable of breaking a chemical bond can be estimated as $\lambda = hc/E.$
UV-A $(\pu{380 nm})$ can break bonds with the energy up to $\pu{315 kJ mol^-1},$ UV-B $(\pu{...
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