33 votes
Accepted

Is alcohol really a solution?

Technically, alcohol is the name of a class of organic compounds containing one or several hydroxyl groups. Colloquially, the term "alcohol" is understood as you have described: A solution (of ...
  • 10.6k
28 votes
Accepted

What chemical properties of ethanol make it usable for drinks as compared to that of methanol?

The problem arises from the metabolized products of methanol. Methanol oxidizes in the liver by an enzyme called alcohol dehydrogenase to formaldehyde which is further metabolized to formic acid by ...
  • 22.8k
26 votes

Migratory aptitude in pinacol-pinacolone rearrangement

In the pinacol rearrangement, a 1,2-diol is treated with acid and rearranges to a carbonyl compound. Here is a reaction scheme showing a mechanism for the rearrangement. In this case the molecule is ...
  • 82.6k
21 votes
Accepted

Why is pyridine used when making tosyl esters from alcohols?

The function of pyridine is actually not so simple and not so easy to notice at first glance. There is a fundamental reason why pyridine is used to promote the acylation reaction, which is that it can ...
21 votes

When I burn isopropyl alcohol (IPA), it burns orange. But when I burn ethyl alcohol, it burns totally blue. Why is this?

IPA has a different carbon:hydrogen ratio than ethanol. There is more incomplete combustion occurring with IPA, hence the smoky orange flame and smell of soot. Ethanol combusts more completely, ...
20 votes
Accepted

Un-denaturing industrial alcohol

(I'm no chemist, but here's my take on it) Let's see: I’m an alcoholic, and I really hate having to dole out large amounts of cash to purchase your usual "drinking"-ethanol. So I get this amazing ...
  • 18.1k
18 votes
Accepted

Why do hydroxyl groups only produce a singlet in proton NMR?

You are both right and wrong. At low temperatures, the NMR spectrum will indeed be as you predicted: the $\ce{H}$ from $\ce{OH}$ will produce a quartet and likewise the $\ce{H}$ from $\ce{CH_3}$ will ...
18 votes
Accepted

Ring contraction in pinacol rearrangement of cyclohexane-1,2-diol

Background You don't specify whether we are starting with cis- or trans-cyclohexane-1,2-diol, but it doesn't matter since both isomers will interconvert under the reaction conditions. Therefore we ...
  • 82.6k
18 votes
Accepted

When I burn isopropyl alcohol (IPA), it burns orange. But when I burn ethyl alcohol, it burns totally blue. Why is this?

Interesting observation. The blue flame color of all hydrocarbon fuels is due to the emission small diatomic carbon species such $C_2$ or CH. There is nothing magical about IPA having a yellow flame. ...
  • 33.7k
17 votes
Accepted

Reactions of alcohol with sulfuric acid

This article on Wikipedia says your compound, ethyl sulphate, can be synthesized, by adding sulfuric acid drop-wise to boiling ethanol and temperature should be kept below 413K which agrees with your ...
  • 4,415
17 votes

Why is thionyl chloride preferred for preparing alkyl chlorides from alcohols?

Preparation of alkyl chlorides from alcohols by thionyl chloride is preferred over other methods mentioned because of the following reasons : $$\ce{R-OH + PCl5 → R-Cl + POCl3 + HCl ↑}$$ $$\ce{...
  • 1,379
17 votes
Accepted

Is it correct to say that ethenol is an alcohol?

The golden book states that ethenol is an alcohol: Enols Alkenols; the term refers specifically to vinylic alcohols, which have the structure $\ce{HOCR'=CR2}$. However, the modifier "vinylic"...
  • 6,758
16 votes
Accepted

Why is thionyl chloride preferred for preparing alkyl chlorides from alcohols?

Thionyl chloride is preferred for preparing alkyl chlorides from alcohols because the by-products formed in the reaction are $\ce{SO2}$ and $\ce{HCl}$ which are in gaseous form and escape into the ...
  • 1,316
15 votes

Testing isopropyl alcohol purity

If the isopropanol mixture was bought commercially, the chances that it contains significant amounts of methanol or ethanol are fairly small, I think. (I've never seen commercial isopropanol in the ...
  • 20.4k
15 votes
Accepted

Reaction of alcohols with PCl5 and PCl3

Remember your general chemistry. In an acid-base reaction, the equilibrium favors the side of the reaction with the weaker acid/base pair. Strong bases have weak conjugate acids. Strong acids have ...
  • 41.8k
15 votes
Accepted

What is the name origin of ester?

The term "Essigäther" is actually the German name for ethyl acetate i.e Essig = "vinegar" + Äther = "ether". "vinegar" becomes acetic, hence ethyl acetate ...
  • 22.8k
14 votes
Accepted

Why can't alcohols turn blue litmus red?

Litmus is a weak acid, with a $\mathrm{p}K_\mathrm{a}$ of about 6.5. Alcohols are extremely weak acids, with $\mathrm{p}K_\mathrm{a}$'s (typically) around 17. The litmus itself is a much stronger ...
  • 5,487
14 votes
Accepted

Are there ethanol and methanol analogues with more than one hydroxyl group?

Generally speaking, they're called diols when bearing two hydroxyl groups. If they're on the same C, this is called a geminal diol, if they are on neighboring Cs, they're called vicinal diols. The C ...
12 votes
Accepted

How to explain this acid-catalysed acetal rearrangement mechanistically?

You have managed to draw the correct acyclic hydrolized compound with a decent mechanism. This is a problem that can be solved by numbering the carbon atoms. Number the carbon atoms sequentially ...
  • 41.8k
12 votes

Benzene from cyclopropane-1,2,3-triyltrimethanol in acidic medium

I have not written the steps for carbocation formation, simple dehydration.
12 votes
Accepted

Formation of toluene from (cyclobutane-1,2,3-triyl)trimethanol using conc. sulphuric acid

Seeing the reaction given here, I assume that is an on-paper reaction that takes place and that all three alcoholic groups are dehydrated. The mechanism (on paper) seems to be as follows Dehydration $...
11 votes
Accepted

Synthetic route for the conversion of ethanol to but-1-yne

The first reaction is the conversion of the alcohol to an alkyl chloride using thionyl chloride. The mechanism of the reaction starts with nucleophilic attack of the alcohol oxygen on sulphur, ...
11 votes

Is alcohol really a solution?

Tschoppi’s answer is technically correct, since it is nigh impossible to create a pure compound without any contaminants. The highest-grade liquids I can remember seeing on SigmaAldrich’s web pages ...
  • 64.8k
11 votes
Accepted

Why can't alcohols form hydrogen-bonded dimers like carboxylic acids?

The strength of a hydrogen bond somewhat depends on the $\ce{X-H\bond{...}X}$ angle that the hydrogen-bonding hydrogen forms with the two electronegative elements $\ce{X}$. In our case, carboxylic ...
  • 64.8k
10 votes
Accepted

What is the OH in alcohol?

You could call ethyl alcohol "ethyl hydroxide" analogously to "sodium hydroxide". But it is a poor analogy, since (unlike NaOH) ethyl alcohol is not an ionic compound, does not dissociate in water to ...
  • 9,056
10 votes
Accepted

Does ethanol react with potassium to form potassium ethanolate and hydrogen gas?

You can view water as the simplest alcohol, and indeed, water reacts with all of the Group 1 metals to form hydrogen gas and the corresponding metal hydroxide according to the following equation $\ce{...
  • 82.6k
10 votes

Why does alcohol crack acrylic (plexiglass)?

If a solvent causes an amorphous polymer to craze, this is because the polymer is principally soluble in it. It diffuses into the surface, but without instantly dissolving it, as the polymer chains ...
  • 11.6k
10 votes

Strength of hydrogen bonding in phenol or methanol

Let me answer the second question first, because the answer is so much easier: Of course the hydrogen bond strength depends among others upon the carbon oxygen is attached to. Consider phenol and ...
  • 64.8k
10 votes
Accepted

Is methanol really more acidic than water?

First, water’s $\mathrm{p}K_\mathrm{a}$ in water is $14$ as explained here. This means that $\ce{H2O}$ is slightly dissociated in liquid form, such that $[\ce{H+}] = [\ce{HO-}] = 10^{-7}$. Second, I ...
  • 772
10 votes

Un-denaturing industrial alcohol

The reason criminals don't undenture alcohol is probably because it's cheap and easy to make your own alcohol at home. Plus it's legal in the US (click on G1) and most other English-speaking ...
  • 101

Only top scored, non community-wiki answers of a minimum length are eligible