Questions tagged [halides]

Chemical compounds that contain halogens (group 17 in the Periodic Table) as part of their chemical structure. This tag should only be applied where the halide group is one of the main focuses of the question.

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7
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1answer
227 views

Why does the light catalyzed radical addition of tetrachloromethane to an alkene produce only a single regioisomer?

This reaction always occurs in the following, regiospecific way: $$\ce{CCl4 + R-CH=CH2 ->[$h\nu$] R-CHCl-CH2-CCl3}$$ The same should apparently also happen when there is a carbon that has two ...
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1answer
902 views

Reagents to synthesise butanedioic acid from 1,2-dibromoethane

Why can't we use $\ce{HCN (g)}$ and $\ce{HCl (aq)}$ to convert 1,2-dibromoethane into butanedioic acid? I found out that the answer is $\ce{KCN (aq/alcoholic)}$ and $\ce{H2SO4 (aq)}$, I don't ...
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1answer
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Why don't hydride shifts occur with hydrohalogenation of 4-methyl-cyclohexene?

My book (see bottom) implies that hydrohalogenation of 4-methyl-cyclohexene follows this mechanism: Why not undergo consecutive hydride shifts to furnish a tertiary carbocation? I would guess that ...
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2answers
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Percentage of yield reaction question

By bubbling $\ce{Cl2}$ in a solution containing $176.6~\mathrm{g}$ of $\ce{MgBr2}$ are obtained [sic!] $135~\mathrm{g}$ of $\ce{Br2}$. However, the yield of this reaction is not $100~\%$. How many ...
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4answers
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Order of Basicity of Nitrogen Trihalides

I was asked to arrange nitrogen tri-halides in order of increasing basicity. On looking up the answer online, it turned out to be the following: $\ce{NF3}$ < $\ce{NCl3}$ < $\ce{NBr3}$ < $\ce{...
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1answer
245 views

Why is the ester bond stable under Reformatsky reaction conditions?

The following reaction is a Reformatsky reaction. Why is the ester bond not attacked in the last step? Couldn’t $\ce{OR3}$ be replaced by $\ce{OH}$ or $\ce{O(molecule)}$?
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3answers
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How to bleach polyester [closed]

I have a challenge. I recently bought a cotton/polyester coat with the intention of bleaching it to near-white. To my surprise, normal bleach with sodium hypochlorite had very little effect. It ...
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Why does chloromethane have a larger dipole moment than chloroform?

Why does $\ce{CH3Cl}$, methyl chloride, have a larger dipole moment than $\ce{CHCl3}$, chloroform? Let us consider $\ce{C-Cl}$ bond moment to be $x$ and that of $\ce{C-H}$ bond to be $y$. In $\...
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2answers
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What happens chemically to 5'-radiolabeled aqueous thyroxine (thyroid prohormone) when its I-131 undergoes beta+gamma decay?

Related to this question about $\ce{^{14}C}$ beta decay in $\ce{CO2}$, what happens when the $\ce{^{131}I}$ in radiolabeled thyroxine (thyroid prohormone, or "T$_4$") undergoes beta-plus-gamma decay ...
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1answer
127 views

Degradation of sulfuryl fluoride SO2F2

Recently, the houses next to us were fumigated with "Vikane", which apparently is $\ce{SO2F2}$. To my surprise, the gas was just pumped out in the atmosphere without further ado at the end of the ...
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2answers
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Why is AlF3 soluble in anhydrous HF only in the presence of KF?

I am pondering over that what must be the reason that $\ce{AlF3}$ is insoluble or less soluble in anhydrous $\ce{HF}$? And pageants it is soluble to a good extent only in the presence of $\ce{KF}$? Is ...
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1answer
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Hydrolysing a compound by repeated methyl and hydride shifts

The question is to predict the major product in the following reaction. First of all the proton will abstract the bromide ion resulting in the formation of a primary carbocation which being unstable ...
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1answer
370 views

Can a first degree carbocation form if a methyl shift is possible?

I was going through a reference book when I stumbled upon this question Is that even possible?
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Why is the carbon-fluorine bond stronger than the other haloalkanes? [closed]

What effect makes C-F bond stronger than other halo-alkanes?
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Which chlorine species can act as an oxidizing agent but not as a reducing agent?

Which species can act as an oxidizing agent but not as a reducing agent? (A) $\ce{Cl2}$ (B) $\ce{Cl-}$ (C) $\ce{ClO2-}$ (D) $\ce{ClO4-}$ I thought the answer was A because if $\ce{Cl}$ ...
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1answer
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Hydrolysis of Phosphorus Trichloride

During hydrolysis of a halide of carbon via $\mathrm{S_N2}$ mechanism, the incoming neutral water molecule attacks the partially positive carbon centre from the side opposite to the halide side and ...
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663 views

Rates of hydrolysis in bicyclic and monocyclic compounds

Which of the following compounds, 1-bromo-1-methylcyclohexane 1 or 1-bromobicyclo[2.2.2]octane 2, hydrolyzes faster (under comparable conditions)? It may be acid catalyzed or base catalyzed hydrolysis,...
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1answer
663 views

Hydrolysis of vinyl bromide vs alkyl chloride

Which of the following compounds, 1-bromocyclopent-1-ene 1 or chlorocyclopentane 2, hydrolyses faster than the second under comparable conditions? It may be acid catalysed or base catalyzed hydrolysis ...
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1answer
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Carbon-13 NMR for chloroform

I am slightly confused by what the spectrum would show for carbon-13 NMR of $\ce{CHCl3}$. My initial guess would be that the peak would be split by coupling to both the proton and the 3 chlorines, as ...
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1answer
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What is the hybridisation in BrF5 [duplicate]

What is the hybridisation of $\ce{BrF5}$ ? I find different sources giving different answers. When I approach this problem , I don't find any exceptional case like $\ce{SH6}$ (in which hybridisation ...
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1answer
416 views

What does the molecular orbital scheme of beryllium chloride and hydride look like?

Beryllium is a somewhat fascinating element since it is the only member of the second group that behaves somewhat non-metalish and, e.g. forms a somewhat covalent chloride and a covalent hydride. In ...
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1answer
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Hydrolysis products of chlorides of group 15

$\ce{NCl3}$ on hydrolysis produces $\ce{NH4OH}$ and $\ce{HOCl}$. $\ce{PCl_3}$ when hydrolyzed produces $\ce{P(OH)3}$ i.e. $\ce{H3PO3}$. $\ce{AsCl_3}$ when hydrolyzed produces $\ce{As(OH)3}$. ...
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Structure of xenon hexafluoride

The central atom has a hybridization of $\mathrm{sp^3d^3}$. Thus, its structure should be pentagonal bipyramidal. Why is it not that but a distorted octahedron?
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1answer
628 views

How to determine the stereochemistry after elimination of anti-1-bromo-2-methylcyclohexane?

The question is asking for the product and the answer is C. My expected answer was E. Here's how I tried to solve it: Since Br (the leaving group) is at the equatorial position, the structure would '...
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3answers
691 views

Skeletal formula of methyl chloride

Recently in The Periodic Table, there was a short discussion regarding this structure: At first sight, I couldn't figure out what is the structure. After a quick google search, I came to know it is ...
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1answer
129 views

In a mass spectrum, are there peaks corresponding to a combination of 13C and bromine isotopes?

I just began studying mass spectroscopy and I don't understand why certain peaks are not represented in the mass spectrum graph. Like let's say you have methyl or ethyl bromide. Usually, there are two ...
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1answer
430 views

Why does bromide not react with water when methyl ammonium bromide is dissolved in water?

In the following reaction, the salt $\ce{CH3NH3Br}$ is formed: $$\ce{CH3NH2 + HBr -> CH3NH3Br} $$ In water this dissociates completely into $\ce{CH3NH3+}$ and $\ce{Br-}$ In my chemistry book, it ...
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1answer
438 views

Why does hydroxide attack the carbon atom of methyl iodide (in an Sn2 reaction)?

As the electronegativity difference between carbon and iodine is negligible, why does $\ce{OH-}$ attack the carbon atom (in an $\mathrm{S_N2}$ mechanism) even though carbon doesn't seem to be ...
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1answer
177 views

Why would this rearrangement happen?

So, I am a first year chemistry student and I saw this chemistry reaction on a previous year's test. I attempted to figure out the mechanism, but I'm rather confused as to how the cyclopentane somehow ...
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2answers
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Elimination reaction of 1-bromo-2-phenylcyclopentane

In the following reaction, treating the trans-1-bromo-2-phenylcyclopentane with ethanolic KOH gives an alkene. But in this case, the double bond is on the left side (less substituted) instead of being ...
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0answers
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Why are alkyl halides immiscible with water?

Why are alkyl halides, though polar, immiscible with water? I have tried to solve this question by myself and I believe that it's due to the large energy is needed to break the hydrogen bonds, which ...
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2answers
734 views

Metal reagent in dehalogenation of vicinal dihalides

In the dehalogenation of vicinal dihalides why can't sodium be taken as a reagent? I understand that zinc is taken because it is reactive and rate of reaction would be considerably high and it ...
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1answer
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In the Favorskii rearrangement, why doesn't the base grab the alpha hydrogen of the carbon bearing the halogen?

In the Favorskii rearrangement, the base (like hydroxide) always abstracts the alpha hydrogen of the carbon not bearing the halogen. But to me the hydrogens on the carbon directly connected to the ...
7
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1answer
671 views

Is it the Na+ or the Cl- that gives table salt its taste?

What gives it that salty taste? I'm wondering if it's the $\ce{Na+}$ or the $\ce{Cl-}$. I know that $\ce{KCl}$ also tastes salty, and other salts have different flavours, but where does the saltiness ...
3
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1answer
320 views

Reason for decreased boiling point of hexafluoroisoproponal?

Ethanol and isopropyl alcohol have boiling points 78.37 °C and 82.6 °C respectively. The increase in the boiling point is obvious due to increase in carbon chain length which resulted in increase in ...
4
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1answer
441 views

Trichloride ion (c.f. triiodide ion)

While triiodide ion is commonly known, why is that trichloride ion (and its salts) almost unheard of? While it does exist according to literature, why is the stability of trichloride ion in aqueous ...
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2answers
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Bromination of acetanilide

Why does acetanilide gives exclusively para isomer. I know that -I of nitrogen must decrease the yield of ortho product, but still it should be made in accountable amounts. Where am I going wrong. I ...
4
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2answers
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Best reagents state for air free chemistry. Choosing halide for grignard synthesis

I am planning to synthesize a grignard and I have a choice between the iodo or chloro aryl halide. The iodo is a solid and the chloro is borderline. For my previous reaction I melted the chloro and ...
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1answer
3k views

Thermal stability of interhalogen compounds

I am striving over the question that what would be the stability order of the following interhalogen compounds : $\ce{ClF3, BrF3}$ and $\ce{IF3}$. One probable answer I got is that stability of ...
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2answers
142 views

Which hydrogen halides react with group 14 oxides?

$$\ce{6HF +SiO2->H2SiF6 +2H2O}$$ $\ce{HF}$ reacts with $\ce{SiO2}$ to form $\ce{H2SiF6}$. Do other hydrogen halides like $\ce{HCl}$ and $\ce{HBr}$ react with group 14 oxides in the same way?
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Why is thionyl chloride preferred for preparing alkyl chlorides from alcohols?

Why is thionyl chloride ($\ce{SOCl2}$) preferred for preparing alkyl chlorides from alcohols, as opposed to say $\ce{PCl5}$ or $\ce{PCl3}$ ?
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1answer
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Iodine test for Starch

The starch and iodide test is to detect amylose, a polysaccharide. We add an iodide solution to a sample and observe a color change with the starch; it turns dark blue. While researching information ...
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2answers
511 views

Is the 5d orbital involved in triiodide ion?

Is the $5\mathrm{d}$ orbital involved in the triiodide ion, $\ce{I3-}$? There are $5$ electron pairs around the central iodine. (Almost) all of the hypervalent compounds involve the most ...
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3answers
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Why can't primary alcohols react with sodium bromide via an SN2 mechanism?

I was told that a primary alcohol reacts with $\ce{HBr}$ for example, but not with $\ce{NaBr}$ through the $\mathrm{S_N2}$ mechanism in the same reaction environment. Why? This reaction can occur: $$...
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0answers
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Can the directionality of an SN2 reaction depend on solvent polarity?

Because of the effects of solvation, halide ions have differing nucleophilicity in protic solvents vs aprotic solvents, iodide being the best nucleophile in protic solvents and fluoride being best in ...
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2answers
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Why do halogen substituents make molecules more lipophilic?

According to my medicinal chemistry text book, halogens increase a drug’s lipophilicty. This makes no sense to me for two reasons: Halogens are all quite electronegative and they will form a $\ce{C-X}...
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2answers
2k views

Gauche effect and bond length

Which of the following compounds has the longest bond length? (A) $\ce{H3C-CF3}$ (B) $\ce{FCH2-CH2F}$ (C) $\ce{F2CH-CHF2}$ (D) $\ce{F3C-CF3}$ My logic was based on the relative ...
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1answer
5k views

Why is it possible to form bromoalkanes but not iodoalkanes from free radical substitution?

For a free radical substitution (FRS) reaction between iodine $\ce{I2}$ with ethane and bromine $\ce{Br2}$ with ethane $\ce{CH3CH3}$: $E_\mathrm d(\ce{H-I})=299\ \mathrm{kJ\ mol^{-1}}$ $E_\mathrm d(\...
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3answers
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Predict which hydrogen is more acidic in the following organic compounds?

Between 2-chloro-2-phenylpropionic acid and hydrogen phthalate, which is the more acidic compound? I'd say the $\ce{H}$ on the second one is more acidic as the $\ce{-COOH}$ group is directly attached ...
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1answer
464 views

Can thionyl bromide produce alkyl bromides?

Thionyl chloride ($\ce{SOCl2}$) is used with alcohols to produce alkyl chlorides. Similarly, can thionyl bromide ($\ce{SOBr2}$) be used with alcohols to produce alkyl bromides?

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