Alcohol Hydroxyl Group

Organic chemistry has always been a vast subject of research among science enthusiasts. The idea of basic organic chemistry is to propagate elementary information about the organic compounds that exist around us and provide a solid foundation for the further exploration of organic compounds and the factors that govern the properties of these compounds. The organic compounds form a series, known as the homologous series in which the successive compounds contain the same functional groups and differ from one another by a –CH2 group. Alcohol is one of the many functional groups found in organic compounds. In this article, we will learn about alcohol structure, phenol structure, and other structures.

Table of contents

What is Alcohol?

Alcohols are the organic compounds in which a hydrogen atom or an aliphatic carbon is replaced with the hydroxyl group. Thus an alcohol molecule consists of two parts; one containing the alkyl group and the other containing the hydroxyl group. They have a sweet odour. They exhibit a unique set of physical and chemical properties. These physical and chemical properties of alcohols are mainly due to the presence of hydroxyl group. The alcohol structure depends on various factors.

Alcohol Structure

Alcohol structure is mainly attributed to the presence of the hydroxyl group. In alcohols, the carbon atom of the main chain is bonded to the oxygen atom of the hydroxyl group by a sigma (σ) bond. This sigma bond is formed due to the overlap of an sp3 hybridized orbital of carbon with an sp3 hybridized orbital of oxygen. Due to the repulsion between the unshared electron pairs of oxygen, the bond angle of C-O-H bonds in alcohols is slightly less than the tetrahedral angle (109°-28′).

Alcohol Hydroxyl group 01

Phenol structure

Phenol structure is mainly attributed to two factors:

  1. Partial double bond character due to the resonance in the aromatic ring because of a conjugated electron pair of oxygen.
  2. The carbon atom attached to oxygen is sp2 hybridized in phenol.

Hence, the C-O bond length in phenol is slightly less than that in methanol.

Alcohol Hydroxyl group 02

Ether structure

  1. An ether molecule has a tetrahedral structure.
  2. Due to the repulsive interaction between the two bulky (–R) groups, the bond angle (R-O-R) is slightly greater than the tetrahedral angle.
  3. The C–O bond length in ether is almost the same as in alcohols.

Alcohol Hydroxyl group 03

For the nomenclature of alcohol, phenol and ether you may visit

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Frequently Asked Questions – FAQs


Why does phenol turn pink after long-standing?

On standing for a long time phenol gets oxidized in the presence of air and turns pink in colour. During oxidation, phenol gets oxidised to quinone and then quinone combines with the phenol to give phenoquinone, which is pink in colour.


What is the common name of the simplest ether?

The simplest ether is CH3OCH3, its common name is Dimethyl ether.


How do you turn alcohol into the ether?

Primary alcohols are converted to ethers on heating in the presence of an acid catalyst. This kind of reaction is called a condensation reaction. In this case, two alcohol molecules combine to give an ether and water.


Does alcohol have a hydroxyl group?

The hydroxyl group is a functional group, alcohol is the organic compound which contains one or more hydroxyl groups attached to the alkyl group.


Is carboxylic acid a hydroxyl group?

Carboxylic acid is a class of organic compounds which contains a carbon atom which is doubly bonded with an oxygen atom and singly bonded with a hydroxyl group. I.e -COOH

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