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Why does adding D2O remove OH peak in NMR spectroscopy? |
[![(1R,2S)‐1,2‐dibromocyclopentane and (1R,3S)‐1,3‐dibromocyclopentane][1]][1]
Are these positional isomers or not? According to me they are, since Br substituent is located at different positions in both the pictures, but the answer key in one of my mock test websites says they're not. Can someone please guide me?
... |
Are (1R,2S)‐1,2‐dibromocyclopentane and (1R,3S)‐1,3‐dibromocyclopentane positional isomers? |
### Problem
> [![reduction of 2,2,3‐trimethyloxirane][1]][1]
### Answer
>! (c) $x = \ce{LiAlH4},~y = \ce{LiAlH4}/\ce{AlCl3}$
### Questions
I know $\ce {LiAlH4}$ is a reducing agent because it gives four $\ce{H-}$ and will attack on our reactant on carbon with less substituents, i.e. in this case on $\ce{... |
### Problem
> [![reduction of 2,2,3‐trimethyloxirane][1]][1]
### Answer
>! (c) $x = \ce{LiAlH4},~y = \ce{LiAlH4}/\ce{AlCl3}$
### Questions
I know $\ce {LiAlH4}$ is a reducing agent because it gives four $\ce{H-}$ and will attack on our reactant on carbon with less substituents, i.e. in this case on $\ce{... |
I have a task to write a formula for 2,4 dimethyl-hexane-1-ol.
If I am incorrect, please suggest me how to write it, but I believe it should look like this:
CH3-CH2-CH2-CH2-CH-CH2-CH2-CH2
/
OH
So it has 8 C, 16 H and 1 O, but I am not sure if that is where the OH should go (4th CH ... |
How do I write alchohol formulas? |
I have a task to write a formula for 2,4 dimethyl-hexane-1-ol.
If I am incorrect, please suggest me how to write it, but I believe it should look like this:
CH3-CH2-CH2-CH2-CH-CH2-CH2-CH2
/
OH
So it has 8 C, 16 H and 1 O, but I am not sure if that is where the OH should go (4th CH ... |
When $\ce{D2O}$ is added to a sample, the OH and NH peaks in a $\ce{^1H}$ NMR spectrum disappear. This is the basis of (for example) the $\ce{D2O}$ [shake test](http://u-of-o-nmr-facility.blogspot.com/2007/10/proton-nmr-assignment-tools-d2o-shake.html).
What causes them to disappear from the spectrum? |
Why does the addition of heavy water cause OH and NH peaks in NMR spectra to disappear? |
When $\ce{D2O}$ is added to a sample, the OH and NH peaks in a $\ce{^1H}$ NMR spectrum disappear. This is the basis of (for example) the $\ce{D2O}$ [shake test](http://u-of-o-nmr-facility.blogspot.com/2007/10/proton-nmr-assignment-tools-d2o-shake.html), and is also the reason why peptide/protein NMR is commonly run usi... |
I am asked an interesting question which I have no theoretical minimum with which to solve. I would like to understand more about it on the basis of its fundamental rationale and learn more about other cases where this reasoning may be useful. To limit my scope precisely, I would like a further elaboration of the theor... |
While solving JEE Advanced 2020 (Paper 2) questions, I came across this particular question:
> Q.10 Choose the correct statement(s) among the following.
>
> (**A**) $\ce{SnCl2 · 2 H2O}$ is a reducing agent.
> (**B**) $\ce{SnO2}$ reacts with $\ce{KOH}$ to form $\ce{K2[Sn(OH)6]}.$
> (**C**) A solution of $\ce... |
Does lead(II) chloride dissociate into Pb²⁺ and Cl⁻ ions in HCl? |
According to me, $\ce{MnO4^2-}$ is paramagnetic and $\ce{MnO4^-}$ is diamagnetic.
On the basis of this, the corresponding potassium salts inherit these magnetic properties, i.e. $\ce{K2MnO4}$ is paramagnetic and $\ce{KMnO4}$ is diamagnetic.
However, according to my class teacher $\ce{KMnO4}$ is paramagnetic.
Is ... |
### Problem
> The hydrocarbon which can react with sodium in liquid ammonia is?
>
> (**A**) $\ce{CH3CH2C#CH}$
> (**B**) $\ce{CH3CH=CHCH3}$
> (**C**) $\ce{CH3CH2C#CCH2CH3}$
> (**D**) $\ce{CH3CH2CH2C#CCH2CH2CH3}$
### Answer
>! **A** $\ce{CH3CH2C#CH}$
### Question
I am confused why the answer ca... |
### Problem
> The hydrocarbon which can react with sodium in liquid ammonia is
>
> (**1**) $\ce{CH3CH2CH2C#CCH2CH2CH3}$
> (**2**) $\ce{CH3CH2C#CH}$
> (**3**) $\ce{CH3CH=CHCH3}$
> (**4**) $\ce{CH3CH2C#CCH2CH3}$
### Solution
>! Solve it as a case of terminal alkynes, otherwise all alkynes react with... |
Which of the following hydrocarbons react with sodium in liquid ammonia? |
### Problem
> The hydrocarbon which can react with sodium in liquid ammonia is?
>
> (**A**) $\ce{CH3CH2C#CH}$
> (**B**) $\ce{CH3CH=CHCH3}$
> (**C**) $\ce{CH3CH2C#CCH2CH3}$
> (**D**) $\ce{CH3CH2CH2C#CCH2CH2CH3}$
### Answer
>! (**A**) $\ce{CH3CH2C#CH}$
### Question
I am confused why the answer ... |
Why is the intensity of the IR spectra of IBr higher than that of ICl?
I know that the IR spectra intensities are proportional to the derivative of the dipole moment with internuclear distance. However, how would one be able to deduce (without looking at the IR spectra) that the IR spectra for IBR is higher than ICL... |
Why is the intensity of the IR spectra of IBR higher than that of ICL? |
Why is the intensity of the IR spectra of $\ce{IBr}$ higher than that of $\ce{ICl}$?
I know that the IR spectra intensities are proportional to the derivative of the dipole moment with internuclear distance. However, how would one be able to deduce (without looking at the IR spectra) that the IR spectra for $\ce{IBr... |
Why is the intensity of the IR spectra of IBr higher than that of ICl? |
Which atoms in indole posses the greatest amount of electron density? |
Which atoms in indole possess the greatest amount of electron density? |
Is there a computer program capable of showing protein conformational changes based on pH? |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/wIDjO.png
Can you explain why phenitoin is weak acid even though nitrogen is base?
Does carbonyl group always make structure acid?
|
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/wIDjO.png
Can you explain why phenitoin is weak acid even though nitrogen is base?
Does carbonyl group always make structure acid?
If this structure doesn't have carbonyl group, would it be base not acid?
|
> [OP] On today's convention; how we define the zero value, positive value and negative values of phi and psi dihedral angle?
In general, you have four atoms (1, 2, 3, 4) in a chain to define a torsion angle. You rotate around the bond connecting atom 2 with atom 3 to change the torsion angle (bond angles and length... |
> [OP] On today's convention; how we define the zero value, positive value and negative values of phi and psi dihedral angle?
In general, you have four atoms (1, 2, 3, 4) in a chain to define a torsion angle. You rotate around the bond connecting atom 2 with atom 3 to change the torsion angle (bond angles and length... |
> [OP] On today's convention; how we define the zero value, positive value and negative values of phi and psi dihedral angle?
In general, you have four atoms (1, 2, 3, 4) in a chain to define a torsion angle. You rotate around the bond connecting atom 2 with atom 3 to change the torsion angle (bond angles and length... |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/xUObF.png
Why is sulthiam base even hough sulfur can accept the electron by resonance from nitrogen
like carbonyl group do? |
Its known that sp3d hybridization has 5 lobes, 3 equatorial with sp2 lobes and 2 axial with dp lobes, do we have such splitting in sp3d2 and sp3d3 hybridizations too? <br>
What I think is sp3d2 splits into 4 dsp2 lobes and 2 dp lobes (correct me if I'm wrong) |
In some variations of the Rosenmund reduction, I've seen hexane used, as in this equation from [this website;][1]
[![enter image description here][2]][2]
[1]: https://www.masterorganicchemistry.com/2011/08/26/reagent-friday-di-isobutyl-aluminum-hydride-dibal/
[2]: https://i.stack.imgur.com/Wj30r.gif
I... |
It's known that $\ce{sp^3d}$ hybridization has 5 lobes; 3 equatorial with $\ce{sp^2}$ lobes and 2 axial with $\ce{dp}$ lobes. Do we have such splitting in $\ce{sp^3d^2}$ and $\ce{sp^3d^3}$ hybridization states too? <br>
What I think is $\ce{sp^3d^2}$ splits into $4 \ce{dsp^2}$ lobes and $2 \ce{dp}$ lobes.
Is this c... |
In some variations of the Rosenmund reduction, I've seen hexane used, as in this equation from [this website;][1]
[![enter image description here][2]][2]
[1]: https://www.masterorganicchemistry.com/2011/08/26/reagent-friday-di-isobutyl-aluminum-hydride-dibal/
[2]: https://i.stack.imgur.com/Wj30r.gif
I... |
Does (2-Methoxyethyl)benzene undergo nitration at the ortho position (MAJOR product)? |
Why does (2-Methoxyethyl)benzene undergo nitration at the ortho position (MAJOR product)? |
My question is about which oxygen is favored for protonation in acidic conditions. So, R1 and R2 are different in the following diagram (for example, one is propyl but the other is ethyl). I looked up my organic chemistry materials, but only symmetric cases (R1 = R2) were suggested.
[![enter image description here][... |
Which oxygen is favored for protonation when hydrolysis of an acetal occurs? |
Why does (2-methoxyethyl)benzene undergo nitration at the ortho position (major product)? |
Here is a photo from an article (Extraction of boron from salt lake brine using 2-ethyl hexanol, 2016), indicating the reaction mechanism as esterification. However, the written reaction equation (H3BO3 + nROH = H3BO3.nROH) suggests the mechanism as solvation. Should not the reaction be H3BO3 + ROH = H2RBO3 + H2O or so... |
Here is a photo from an article [![][1](Extraction of boron from salt lake brine using 2-ethyl hexanol, 2016), indicating the reaction mechanism as esterification. However, the written reaction equation (H3BO3 + nROH = H3BO3.nROH) suggests the mechanism as solvation. Should not the reaction be H3BO3 + ROH = H2RBO3 + H2... |
Excuse me if the wording in the headline is vague.
I'm trying to read studies about the possible toxicity of the leaves of some plant often said to possess positive medicinal properties.
In the studies, performed on rats, it is usually said that an aqueous and/or ethanol extract of the plant was administered at x... |
When an aqueous extract of a substance is said to be administered at a certain quantity, is the quoted mass analogous to one as original substance? |
Here is a photo from an article, [*Hydrometallurgy* **2016,** *160,* 129–136](https://doi.org/10.1016/j.hydromet.2016.01.001)
> [![enter image description here][1]][1]
This indicates the reaction mechanism as esterification. However, the written reaction equation ($\ce{H3BO3 + nROH -> H3BO3.nROH}$) suggests the ... |
In some variations of the organic reduction by DIBAL-H, I've seen hexane used, as in this equation from [this website;][1]
[![organic reduction by DIBAL-H][2]][2]
[1]: https://www.masterorganicchemistry.com/2011/08/26/reagent-friday-di-isobutyl-aluminum-hydride-dibal/
[2]: https://i.stack.imgur.com/Wj30r... |
please may I know if acetone can be used as a GCMS solvent/diluent for a sample containing ammonia? Will there be a reaction between these two species? |
Can acetone be used as a GCMS solvent for a sample containing ammonia? |
[![phenitoin ][1]][2]
Can you explain why phenitoin is weak acid even though nitrogen is base?
Does carbonyl group always make structure acid?
If this structure doesn't have carbonyl group, would it be base not acid?
[1]: https://i.stack.imgur.com/18HILt.jpg
[2]: https://i.stack.imgur.com/wIDjO.png |
**Background**
Positron emission tomography (PET) is a highly sensitive imaging modality that can provide in vivo quantitative information of biological processes at a biochemical level. PET relies upon the administration of a chemical probe, often called a radiopharmaceutical, that is labeled
with a short-lived posi... |
Carbon 11 radiolabelled inhaledBeta-2 agonist or corticosteroids, is it possible? |
I'm trying to read studies about the possible toxicity of the leaves of some plant often said to possess positive medicinal properties.
In the studies, performed on rats, it is usually said that an aqueous and/or ethanol extract of the plant was administered at $x \ \pu{mg/kg}$ of mice mass, and from that data possi... |
**Background**
Positron emission tomography (PET) is a highly sensitive imaging modality that can provide *in vivo* quantitative information of biological processes at a biochemical level. PET relies upon the administration of a chemical probe, often called a radiopharmaceutical, that is labeled with a short-lived pos... |
Carbon 11 radiolabeled inhaled Beta-2 agonist or corticosteroids, is it possible? |
Why benzene is more easily reduced by Birch reduction than by catalytic hydrogenation? |
If i'm doing an experiment on the effect of temperature on the time taken to produce acetic acid and salicylic, are there any qualitative observations I can make about when the reaction has finished? If required, I am using a 0.01M aspirin in pure water for this experiment. |
I'm doing an experiment on the effect of temperature on the time taken to produce acetic acid and salicylic acid. Are there any qualitative observations I can make about when the reaction has finished?
I am using a 0.01 M aspirin in pure water. |
How can you qualitatively tell when the hydrolysis of aspirin is over? |
**So I find this everywhere:**
"Mixtures showing large deviations from Rault's law form azetropic mixtures at specific compositions"
**My questions are:**
(a)Why is it so?Why deviation from Raoult's law is needed at all.
Wikipedia simply skips over the answer stating its a mathematical consequence.
(Q... |
**So I find this everywhere:**
"Mixtures showing large deviations from Rault's law form azetropic mixtures at specific compositions"
**My questions are:**
(a)Why is it so?Why deviation from Raoult's law is needed at all.
Wikipedia simply skips over the answer stating its a mathematical consequence.
(Q... |
>If we have some solutions, in which we know the temperature and concentration of the solute particles, can we compare their vapour pressures?
For example, if we have 0.02 M $\ce{NaCl}$ at 50$^{\circ}$ C ,0.03 M $\ce{NaCl}$ at 40$^{\circ}$C, 0.005 M $\ce{CaCl_2}$ also at 50$^{\circ}$ C , and some other solution, sa... |
Is there an empirical relatipnship between vapour pressure and concentration/temperature of solution? |
I have a gas reaction which follows the Lindemann-Hinshelwood mechanism and want to calculate the rate constant at low and at high concentrations of the gas but I find myself stuck at what my next step should be and hope someone here could push me in the right direction.
I have that the effective rate constants are... |
>If we have some solutions, in which we know the temperature and concentration of the solute particles, can we compare their vapour pressures?
For example, if we have 0.02 M $\ce{NaCl}$ at 50$^{\circ}$ C ,0.03 M $\ce{NaCl}$ at 40$^{\circ}$C, 0.005 M $\ce{CaCl_2}$ also at 50$^{\circ}$ C , and some other solution, sa... |
Is there an empirical relationship between vapour pressure and concentration/temperature of solution? |
**Why** rate of aromatic nucleophilic substitution of *Ortho*-fluoronitrobenzene is greater than *para*-fluoronitrobenzene?
Kindly note question is about why rate of ortho is greater than para position. Not **meta** position.
This is previous year KVPY question but they had not asked reason and just asked compari... |
A double radical? |
I want to buy bulk activated carbon for use in a DIY air-filtration set-up, like [this](https://www.youtube.com/watch?v=ktUSd6lpm3M), to improve air quality in my bedroom.
From what I understand, the relatively larger sizes of carbon media on the market are optimal [for air filtration](https://charcoalhouse.com/edu... |
Is there a practical re-use value gained by grinding up activated carbon that is spent/saturated? |
Is “double dot” (“··”) notation used for a double radical? |
Why be qualitative when with just a little more effort you can be quantitative?
Acetylsalicylic acid has a pK$_a$ of 2.97, i.e., it is fairly acidic (Ref 1). Salicylic acid, one of the hydrolysis products, is comparably acidic (pK$_a$ = 2.79 Ref 2) and its sodium salt is fairly neutral (pH = 6.0 - 8.5 for a commerci... |
Can we compare the vapour pressure of solutions whose concentrations and temperature is known? |
Сan acetone be used as a GC–MS solvent/diluent for a sample containing ammonia? Will there be a reaction between these two species? |
Can acetone be used as a GC–MS solvent for a sample containing ammonia? |
[Disclaimer: I am aware that this is a very 'first-world problem', 'light-hearted' kind of question, given the health crisis we are still going through. Just to avoid offending anyone, here's an easy solution: no need to continue to read if you disapprove :) ]
I have 3 brands of 'liquid gel', each with rather differ... |
Why there is a color fading ( to colorless) when Cerium Ammonium Nitrate (CAN) is mixed with ethanol or butanol? |
In Grossman, The Art of Writing Reasonable Organic Reaction Mechanisms, he provides the following explanation. The question asks to explain why the difference in pKa values between PhSH and EtSH is much smaller than PhOH and EtOH. In the solutions manual he writes:
[![Grossman, The Art of Writing Reasonable Organic ... |
I discovered that in my laptop settings, I can select an option that is best chosen when the laptop is mainly connected to AC power, and apparently keeps the battery at a lower SOC.
I found this feature also in a Sony smartphone (slightly different operation, it would keep the battery at 90% max during the night, and... |
Why a Li-ion battery, when in storage, is better kept around 85% instead of 100%? |
When calculating pH of methanoic/formic acid (HCOOH) why do we not multiply the molarity by 2 as there are two moles of hydrogen? I mean we do it for sulphuric acid as there are 2 moles of H+ ions but when it comes to HCOOH, it only counts as one?? |
When calculating pH of methanoic/formic acid (HCOOH) why do we not multiply the molarity by 2 as there are two moles of hydrogen? |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/2LMc4.jpg
Im running a soxhlet extraction using hexane as the solvent. Once the hexane has filled up the soxhlet, a considerable amount of hexane will come out on top of the condenser. Is this an issue with pressure or defects in the glass... |
I understand how to find the valency of atoms in small organic compounds. For instance, for CH4, the valency of carbon is 4, while the valency of each hydrogen is 1. But for a coordination compound, for instance:
[![enter image description here][1]][1]
**How do I find the valency of the center metal?**
I need... |
>If we have some solutions, in which we know the temperature and concentration of the solute particles, can we compare their vapour pressures?
For example, if we have 0.02 M $\ce{NaCl}$ at 50$^{\circ}$ C ,0.03 M $\ce{NaCl}$ at 40$^{\circ}$C, 0.005 M $\ce{CaCl_2}$ also at 50$^{\circ}$ C , and some other solution, sa... |
I understand how to find the valency of atoms in small organic compounds. For instance, for CH4, the valency of carbon is 4, while the valency of each hydrogen is 1. But for a coordination complex, for instance:
[![enter image description here][1]][1]
**How do I find the valency of the center metal?**
And if t... |
>If we have some solutions, in which we know the temperature and concentration of the solute particles, can we compare their vapour pressures?
**Original question:**
>Which solution has the highest vapour pressure among the following?
>
>**a)** $0.02 ~\pu M ~\ce{NaCl}$ at $50^{\circ}$C **b)** $0.03 ~\pu{M}$ sucro... |
The following reaction seem to be valid;
$\ce{CH2OH-CHOH-CH2OH ->[HIO4]CH2O + HCOOH + CH2O + 2H2O}$
Apparently, there are similar reactions by 2,3-dihydroxypropanal, and also by the straight chain form of fructose.
The first two reactions involve doing the Malaprade reaction on molecules with adjacent alcohol ... |
Periodic acid oxidation of carbonyls? |
Can the solvent fraction of a sol-gel process containing tetraethyl orthosilicate (TEOS) be analyzed by GCMS? I am worried that the easy polymerization of TEOS to form silica (SiO2) will ruin the GCMS system. |
Can the solvent fraction of a sol-gel process containing tetraethyl orthosilicate (TEOS) be analyzed by GCMS? |
[ This is a short answer, as a complete answer would require going through multiple references and books on the topic. ]
First of all, the ESI process does not require the pH to be acidic : positive ESI is routinely done in ammonium acetate or ammonium bicarbonate media, which have a pH of 7.4 or 8.1. But indeed, to... |
I found an organic chemistry question which asked the major product of the following reaction -
[![enter image description here][1]][1]
The mechanism for the same in the answer was -
[![enter image description here][2]][2]
[1]: https://i.stack.imgur.com/jdLP4.png
[2]: https://i.stack.imgur.com/Gf... |
On which side is the intermediate carbocation formed during acid-catalyzed opening of epoxide? |
Is the refractive index of a solution of four substances the median of the four substances' refractive index? |
Given a reaction involving an acid chloride with sodium acetate in acetic acid, what would the first step be? |
I found an organic chemistry question which asked the major product of the following reaction -
[![enter image description here][1]][1]
The mechanism for the same in the answer was -
[![enter image description here][2]][2]
[1]: https://i.stack.imgur.com/jdLP4.png
[2]: https://i.stack.imgur.com/Gf... |
"In general, Friedel-Craft's alkylation is not employed to make monoalkyl benzene derivatives because of the polysubstitution." writes in our lab manual.
But our proffessor told us that while we do thisexperiment, polysubstitution is quiet impossible.
Phenol + t-butyl chloride (AlCl3 catalyst)--> para-t-butyl pheno... |
Why doesn't polysubstitution occur in this Friedel-Craft's Alkylation Reaction? |
"In general, Friedel-Craft's alkylation is not employed to make monoalkyl benzene derivatives because of the polysubstitution." writes in our lab manual.
But our proffessor told us that while we do thisexperiment, polysubstitution is quiet impossible.
Phenol + t-butyl chloride (AlCl3 catalyst)--> para-t-butyl pheno... |
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