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Questions tagged [phenols]

Use this tag for questions about phenols, their synthesis, analysis, properties and more. Do not use the 'alcohols' tag for phenols due to the differences between the two classes.

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26 votes
4 answers

Why is acetic acid more acidic than phenol?

Acetic acid (ethanoic acid, $\mathrm pK_\mathrm a \approx 5$) is more acidic than phenol ($\mathrm pK_\mathrm a \approx 10$), which is reflected in their reactivity with a weak base such as sodium ...
Manisha Poudel's user avatar
16 votes
3 answers

Friedel–Crafts reaction of phenol

Does phenol undergo Friedel–Crafts reactions or does it react with Lewis acids like aniline does?
user63762453's user avatar
35 votes
1 answer

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, ...
mannaia's user avatar
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27 votes
2 answers

Electrophilic Aromatic Substitution: Are protonated OH-groups ortho-/para- or meta-directing?

In Electrophilic Aromatic Substitution ($\text{S}_{\text{E}}\text{Ar}$) reactions groups that can donate an electron pair into the aromatic ring, e.g. $\ce{-OH}$ or $\ce{-NH2}$, are ortho-/para-...
Philipp's user avatar
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16 votes
1 answer

What is the product of the chemical reaction between phenol and ferric chloride?

The chemical reaction between phenol and ferric chloride is a test for the presence of phenol. They react with each other to produce a violet complex. However, the reaction is given differently in ...
Nilay Ghosh's user avatar
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2 votes
1 answer

Why can't picric acid be made more acidic by adding nitro groups at the meta positions?

I understand that picric acid is acidic because of the $\ce{-NO2}$ electron withdrawing group, but why can't we add more of those on the meta positions to make it more acidic? Is it because that $\ce{-...
User10001010001000's user avatar
44 votes
1 answer

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 ...
Kartik Anand's user avatar
22 votes
4 answers

Reason for the stronger acidic property of phenol than alcohol

In phenol, pulling the $\mathrm{p}_z$ electrons from the oxygen atom into the ring causes the hydrogen atom to be more partially positive than it is in aliphatic alcohols. This means it is much more ...
Eliza's user avatar
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22 votes
4 answers

Acidity order of nitrophenols

As in other posts I have seen and learnt that, if one is given four compounds, namely para-nitrophenol, ortho-nitrophenol, meta-nitrophenol and phenol and is told to arrange them in order of acidity, ...
Aneek's user avatar
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19 votes
3 answers

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 ...
Dhruba Banerjee's user avatar
11 votes
3 answers

Inductive vs resonance effects and the acidity of phenol

A lot of people rationalize the acidity of phenol by saying that resonance is responsible for much of phenol's acidity as opposed to aliphatic alcohols. However, this image suggests that in fact the ...
Dissenter's user avatar
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6 votes
1 answer

Can the hydroxyl group of 4-hydroxybenzoic acid react with phosphorus pentachloride?

I learned that, a phenol will not react (or react very slowly) with $\ce{PCl5}$ due to its stabilized structure. How about the $\ce{-OH}$ group on the benzene ring of 4-hydroxybenzoic acid? Will that ...
txn's user avatar
  • 101
12 votes
1 answer

Why is picric acid more acidic than carbonic acid?

I just had a question in a test asking to compare the relative acidity of picric acid (TNP) and carbonic acid, $\ce{H2CO3}$ (not phenol). It turns out that TNP is more acidic. I have no idea why? Is ...
Ashwin Suryanarayanan's user avatar
11 votes
1 answer

Reaction of phenol and zinc dust

There is a reduction reaction of phenol with zinc dust which is found in many books. $\ce{Ph-OH + Zn -> Benzene + ZnO}$ However, a simple google search fails to explain anything about the ...
S R Maiti's user avatar
  • 5,685
7 votes
1 answer

Synthesis of 2-methyl-4-nitrophenol from benzene?

Benzene first reacts with the reagents $\ce{CH3Cl/AlCl3}$, to attach a methyl ($\ce{CH3}$) group to the benzene ring. Then I suggested reacting with $\ce{OH-}$. Because the methyl group is an ...
Karen Palacios Alfonso's user avatar
6 votes
2 answers

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 ...
Kara's user avatar
  • 61
3 votes
1 answer

Reactions of phloroglucinol

Does phloroglucinol respond to the iodoform test? cerric ammonium nitrate test? 2,4-DNP test? I couldn't find any good sources that answer any of these. I thought of this: Tautomerism can "change" ...
Shourya Pandey's user avatar
14 votes
3 answers

Gattermann-Koch Reaction with Phenol Substrates

The Gattermann-Koch Reaction involves the formation of an aryl aldehyde using carbon monoxide and hydrochloric acid as reactants. The reaction is catalyzed by aluminium trichloride in the presence of ...
tkhanna42's user avatar
  • 2,545
11 votes
2 answers

Can phenol be detected with a ceric ammonium nitrate test?

Today, I came across a question which asked name three reagents can be used for identification of phenol. The answer given was: Neutral $\ce{FeCl3}$ $\ce{ NaNO2 +HCl}$ $\ce {(NH4)2[Ce(NO3)...
Arvind Tiwari's user avatar
10 votes
1 answer

Why is quinone mono oxime more stable than 4-nitrosophenol?

When we do nitrosation of phenols, we get para-nitrosophenol as the major product, which tautomerises to quinone mono oxime. This article states that it largely exists in the quinonoid form. My ...
V.G's user avatar
  • 1,251
7 votes
0 answers

Why is o-fluorophenol a stronger acid than p-fluorophenol?

The $\mathrm{p}K_\mathrm{a}$ value of o-fluorophenol is $8.7$, while that of the p-fluorophenol is $9.9$. It's obvious that the inductive effect is more dominant at ortho-position, which results in a ...
whateven's user avatar
  • 239
6 votes
1 answer

Nomenclature of benzene derivatives with two functional groups

In several places, I have seen that while naming benzene derivatives, no priority for substituents is followed. For example, I've seen both 2-hydroxyaniline and 2-aminophenol being used. Is there an ...
Mahathi Vempati's user avatar
6 votes
0 answers

Diazo Coupling reaction with para-substituted phenol?

Usually Diazo coupling occurs at para-position unless the para-position is occupied, in which case coupling occurs at ortho-position. While solving questions I found in both the cases as shown, the ...
Chloritone_360's user avatar
4 votes
2 answers

Why is meta-nitrophenol less acidic than para-nitrophenol? [closed]

My professor said while explaining the acidic nature of phenol that meta-nitrophenol is less acidic than para-nitrophenol, and gave the reason that resonance doesn't play on meta, but I didn't get it.
Rishabh's user avatar
  • 57
2 votes
2 answers

Intermediates in aqueous bromination of phenol

A question in my book (an archive for IIT JEE exam questions) asks: In the reaction: The intermediate(s) is/are? The correct answers are given as However, as per my knowledge, compound (b) does not ...
Hridai Khurana's user avatar
2 votes
1 answer

Which Phenols give the colours blue, green or violet in the neutral FeCl3 test?

I have read about the neutral FeCl3 test for Phenols, where a positive test is indicated by the colour of the solution which ranges from green to blue to violet. But which specific derivatives of ...
Akhil Lasrado's user avatar
1 vote
1 answer

Physical properties of phenols

Order of increasing boiling point is p-nitrophenol > m-nitrophenol > o-nitrophenol. The difference between bp of p- and o-nitrophenol is that one form intermolecular hydrogen bonding while other form ...
N.D's user avatar
  • 13
0 votes
3 answers

Is there an intramolecular hydrogen bond in guaiacol?

Is there a hydrogen bond between the $\ce{H}$ atom of $\ce{-OH}$ group and the $\ce{O}$ atom of the $\ce{-OCH3}$ group in ortho-methoxyphenol? I was told no. But I want to know why.
Govind Balaji S's user avatar
0 votes
2 answers

Between 3-chlorophenol and 3-fluorophenol, which one is more acidic?

Between 3-chlorophenol and 3-fluorophenol, which one is more acidic? In this case, I know that both F and Cl are electron-donating groups. Furthermore, I know that F is more electron-donating than ...
Michael Polerman's user avatar