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Questions tagged [reactivity]

Applied to a chemical species, the term expresses a kinetic property in reference to another species. The tag should be applied to questions seeking answers with respect to the reactivity (or unreactivity) of a certain chemical compound, species, molecular entity and/or functional groups. It must not be applied to questions about the stability of certain chemical species.

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Why is the HOMO always lower in energy than the LUMO?

We say that increasing the energy of the $\ce {HOMO}$ of molecules increases their reactivity towards electrophiles while decreasing the energy of the $\ce {LUMO}$ increases their reactivity towards ...
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At what acid concentration does potassium metabisulfite react?

I'm in the process of developing a well preserved food-stuff containing potassium metabisulfite and a number of acids (acetic, ascorbic, malic, tartaric, citric, lactic). Wine-making literature ...
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Why are “diene” structures in the C-ring of anthocyanins singled out for their singlet-oxygen quenching ability?

Anthocyanins are a class of water-soluble vacuolar pigments. They are sensitive to pH, and can undergo a series of structural changes according to a pH-dependent equilibrium as illustrated in Figure 1....
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Why does nose grease knock down the head on beer and soda?

Freshman year, my first semester, I was taught many things. One important trick I learned was when I was passed a beer in a 12 oz. plastic cup, I could eliminate the fresh foamy head by wiping my ...
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How do I decide whether ring will expand in this reaction or not?

Attempt: After forming the carbocation adjacent to the cyclopropyl ring I had two options, $\ce{Cl-}$ then and there without any changes Expand ring, form a new carbocation and add $\ce{Cl-}$ ...
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Which is easier, the nitration of toluene or the nitration of mesitylene (1,3,5-trimethylbenzene)?

Does the toluene can undergo nitration easier than mesitylene (1,3,5-trimethylbenzene), due to the high repulsion that will occur between $\ce{NO2}$ and the two adjacent methyl groups (in mesitylene ...
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Is there a way to contain fluorine gas for long term so that it can be visually observed?

Bromine, chlorine and iodine can all be sealed in a glass container for display without the elements reacting with the glass. But if you try to seal fluorine in glass I believe it will react and fog ...
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Why do Organolithium or Grignard reagents act as nucleophiles and not as bases with aldehydes and ketones

I've read entire Chapter 14: Organometallic Compounds of Francis Carey's "Organic Chemistry" but I still didn't get an answer to my question. Quote from the book: Because of their basicity ...
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Role of methanol in NaBH4 reduction

In reduction of carbonyls (aldehyde and ketones) to alcohols using NaBH4/Methanol, alkoxides are formed with the Boron which usually gets protonated on addition of water/acid. My question is what is ...
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Equation for reaction between chlorine fluoride and potassium bromide

The equation given in the answer key was $$\ce{ClF + 2KBr → KCl + KF + Br2}$$ However won't the $\ce{KCl}$ also react with $\ce{ClF}$ to form $\ce{KF}$ and $\ce{Cl2}$, resulting in the net reaction ...
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Ketal formation of ethyl acetoacetate

Why does the ketone carbonyl group react in preference to the ester carbonyl? Is it something to do with the resonance occurring into the ester carbonyl from the oxygen? but how does this make the ...
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Stability of carbanion

I am confused about how one can determine the stability of carbanions using pKa-values. I know that the stability of carbanions can be determined by the inductive effect, hybridization of the charged-...
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Derivation of Gibbs free energy formula

Okay, so I'm trying to derive an important formula which states that - ∆G(r) = ∆G° + RTln( RQ ) where ∆G(r) is the instantaneous rate of change of Gibbs energy with ...
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1answer
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Why is liquid oxygen more reactive than gaseous oxygen?

Liquid oxygen is somewhat hairy to work with, as, if it comes in contact with essentially anything combustible, it has an unfortunate tendency to detonate violently if looked at sideways. Gaseous ...
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How could mass increase when sulfuric acid is added to calcium carbonate?

Context: I was doing an experiment in class that investigates the rate of mass loss over time when $\pu{20 mL}$ of sulfuric acid is added to $\pu{5g}$ of calcium carbonate. I did the experiment 3 ...
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What is the quickest way to dissolve steel?

What is the quickest way to dissolve a large chunk of steel? I mean a very quick reaction, assuming that the interaction occurs in a sealed or semi-sealed environment? Reaction times of the order of a ...
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Why is a hydroxyl group more activating than a methoxy group in electrophilic aromatic substitution?

Why is phenol more reactive towards electrophilic substitution than methoxybenzene? Isn't the lone pair on the methoxy group oxygen more available for participating in resonance into the ring than the ...
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How does ring size affect SN2 reactions?

Suppose we have to compare the $\mathrm{S_N2}$ reactivity order for cyclopropyl and cyclopentyl chloride. How can we do that? I think that cyclopentyl should be more reactive towards $\mathrm{S_N2}$ ...
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What is the reason for more stable keto form to tautomerise to a less stable enol form?

In the mechanism of SeO2 I have seen that a more stable keto form first converts to a less stable enol form and then yields a diketone. I have seen many other reaction where the reactant converts to ...
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Is the water absorbed by sodium polyacrylate available to react?

I'm curious whether the water absorbed by sodium polyacrylate would react with alkali metals, or be trapped by the sodium polyacrylate.
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1answer
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Order of reactivity of hydrogen halides

Solomon and Fryhle $11^{th}$ edition says : Order of reactivity of HX in the acid catalyzed conversion of alcohols to alkyl halides follows the order : HI>HBr>HCl We can account for this by saying ...
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In a galvanic cell why does using a more reactive metal increase the voltage?

As the title says, why does using magnesium produce a higher voltage compared to using zinc when reacting with iron? Im having trouble figuring out why the voltage changes. magnesium+copper > zinc+...
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Why is benzenediazonium fluoroborate water insoluble and stable at room temperature?

Benzenediazonium fluoroborate is water insoluble and stable at room temperature. Why is this salt, water insoluble? Also I am told that benzenediazonium salts are stable only at low temperature(<5°...
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1answer
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Does aluminum oxide react with rubidium?

I have rubidium vapor inside of the vacuum chamber. Inside the vacuum chamber, there are two flat stainless steel coated with aluminum oxide at temperature ~100 °C. Since rubidium is active, I am ...
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1answer
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Rationalising the reactivity of phosphoryl chloride

$\ce {POCl3}$ is a reagent well-known for enacting various functions in organic synthesis. For example, together with pyridine, it is able to dehydrate alcohols to give alkenes. Also, reacting it with ...
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Reaction between NaOH and Carbonic acid

I was presented with the following reaction when we were just learning about acids and bases: $$\ce{2NaOH + H2CO3 -> H2O + Na2CO3}$$ however I had thought it might've been something like $$\ce{...
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Reactivity series of metal

I have learned about metal and their reactivity series. However, why metals have different reactivity? What are the factors of different reactivity rate for metal? All I can think of is the number of ...
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1answer
2k views

Is calcium hydroxide or potassium hydroxide more efficient at removing carbon dioxide?

In biology, we commonly use $\ce{KOH}$ in respirometers to remove carbon dioxide. A common test in chemistry to detect the presence of carbon dioxide is to bubble it through limewater, turning it ...
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Why does calcium oxide react with sulfur dioxide?

Which of the following compounds reacts with calcium oxide, $\ce{CaO}$? (a) $\ce{K2O}$ (b) $\ce{Na2O}$ (c) $\ce{SO2}$ (d) $\ce{MgO}$ I thought that since sodium is higher in the reactivity ...
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Reactivity of primary and tertiary alkyl halides

From USNCO 2004, Q58: The reaction between which pair of reactants occurs the fastest for $[\ce{OH-}] = \pu{0.010 M}$? (A) $\ce{CH3CH2CH2CH2Cl + OH-}$ (B) $\ce{(CH3)3CCl + OH-}$ (C) $...
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How do we know whether we will get a mono substituted or tri-substituted product during electrophilic aromatic substitution?

For example consider the bromination of phenol we get the tri-substituted product (even though bromine is deactivating so I suppose it should deactivate the ring with each addition) while sulphonation ...
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Where will a H+ attack on 6-hydroxyhexan-2-one? [closed]

Where will a H+ attack on 6-hydroxyhexan-2-one? Protonation can take place either on the ketone or the alcohol. So where will it attack? In short, on which of the two oxygen atoms is electron density ...
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Why is gold unreactive when only one electron is in the outer shell?

I've been trying to answer my (high school) daughter's questions about the periodic table, and the reactivity series, but we keep hitting gaps in my knowledge. So I showed that the noble gases have a ...
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4answers
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Which is more reactive, chlorine radical or chloride ion?

Ions are very reactive for obvious reasons (i.e. Coulomb force); $\ce{Cl-}$ ions will be very quick to form an ionic bond with positive ions (unless inhibited, e.g. through being in a solution; let's ...
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If glucose can react with phenyl hydrazine to form osazone why can't it react with 2,4-DNP to give positive test?

If glucose can react with form phenyl hydrazine to form osazone why can't it react with 2,4-DNP? Yes I know about cyclic form of glucose and its equilibrium with straight chain and all … I read ...
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1answer
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Would atomic oxygen and atomic hydrogen result in O2 and H2 only, or some H2O too? [closed]

Let's assume we have atomic oxygen and atomic hydrogen in a closed chamber, the temperature and pressure of which we're able to monitor (and control). Number of hydrogen atoms are twice that of oxygen....
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Definition of Nucleophilicity

I have a rather quick question on the definition of Nucleophilicity. To get straight to the point, am I right in saying that the most appropriate definition of Nucleophilicity, regardless of whether ...
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How is fluorine gas contained and transported, why aren't the metal cylinder and tube in this video attacked?

I included the GIF below as part of an answer to Can paper burn without oxygen or air?. It was made from the video Fluorine - Periodic Table of Videos. I noticed that the cylinder containing the ...
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1answer
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What is a barrier-less reaction in Quantum Chemistry?

After finding a reaction "Transitional State" by GAMESS, and finding Hessian Eigenvalues, my project instructor said: seems your imaginary frequency (negative eigenvalue) is not that big (it is ...
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1answer
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What can be added to hydrochloric acid to make a gel or paste?

I have a bottle of brick cleaner containing 18-20% hydrochloric acid. What can I add to it to make a gel or paste without unwanted reactions? The application is still just cleaning bricks as the ...
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Is methoxide a better nucleophile than hydroxide?

What is more nucleophilic, $\ce{OH-}$ or $\ce{CH3O-}$? When I look it from the viewpoint of steric hindrance, the answer seems to be $\ce{OH-}$, but when I see it from the viewpoint of extra electron ...
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why fluorine and oxygen have different behaviour towards electron gain enthalapy and electronegativity? [closed]

I have seen following definitions in my textbook: Electron gain enthalapy may be defined as enthalpy change taking place when an isolated gaseous atom of the element accepts an electron to form a ...
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2answers
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How can I predict if a reaction will occur between any two (or more) substances?

I am new to chemistry and I find it fascinating. I am trying to learn about chemical reactions and I was wondering if there was an easy way to quickly tell if any combination of chemical substances ...
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1answer
103 views

Metal reactivity with hot water VS HCL

Does being able to react with hot water take more metal reactivity than being able to react with HCl? To me, it seems like a metal would need to be more reactive to be able to react with hot water ...
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Why is zinc more reactive than copper?

In terms of electronegativity, from what I understand electronegativity increases going across the period, so surely this should mean that zinc less readily loses its outer shell electrons than copper?...
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How does HF dissolve glass?

By what mechanism does HF proceed in dissolving glass? Why is it the only acid that has this capability? Is it because of the small size and high electronegativity of fluorine?
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With which 2 of these 5 chemicals would Chlorine not react? N, NaOH, O2, NaBr, Fe

A question in a Russian EGE test asks to choose 2 chemicals out of 5 with which Chlorine does not react: Nitrogen - I checked and it reacts $\ce{KOH}$ -- reacts $\ce{O2}$ -- reacts $\ce{NaBr}$ -- ...
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Why does zinc react with sodium hydroxide?

If zinc is less reactive than sodium, then why does it still react with sodium hydroxide?
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Rate of EAS in chlorobenzene and fluorobenzene

In both chlorobenzene and fluorobenzene, both the halogens show a −I effect where fluorine has more electron withdrawing effect than chlorine. Now, if we consider the mesomeric/resonance effect, ...
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Why is fluorine more reactive than chlorine?

Why is fluorine more reactive than chlorine despite chlorine having a higher electron affinity?