Properties of Phenol

Phenols are a type of organic compounds that contain a benzene ring which is bonded to a hydroxyl group. They are also called carbolic acids. They exhibit unique physical and chemical properties when compared to alcohol. These physical and chemical properties of phenol are mainly because of the presence of the hydroxyl group in them. Phenols are much similar to alcohols but form much stronger hydrogen bonds than the alcohols. Hence, they are more soluble in water than alcohols and have a higher boiling point. Phenols occur in either the form of colourless liquids or white solids at the room temperature and can be highly toxic and caustic in nature. In this article, we will learn about the properties of phenol in detail and include both the physical properties of phenol and the chemical properties of phenol.

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Properties of Phenol in Detail

1. Boiling Point of Phenol

Phenols usually have a higher boiling point when compared to the other hydrocarbons that have equal molecular masses. This is because of the presence of the intermolecular hydrogen bonding between the hydroxyl groups of the phenol molecules. In general, the boiling point of phenol increases when there is an increase in the number of carbon atoms.

2. Solubility of Phenol

The solubility of phenol in water is generally decided by the hydroxyl group that is present.

The hydroxyl group in phenol is involved to form the intermolecular hydrogen bonding.

Therefore, these hydrogen bonds are formed between water and phenol molecules that make phenol soluble in water.

However, the aryl group that is attached to the hydroxyl group is hydrophobic.

Hence, the solubility of phenol tends to decrease with an increase in the size of the aryl group present.

3. Acidity of Phenols

Phenols react with active metals like sodium, potassium, etc. and form the corresponding phenoxide. These reactions of phenols say about them that they are acidic in nature. In phenol, the sp2 hybridized carbon in the benzene ring which is attached directly to the hydroxyl group acts as the electron-withdrawing group. Therefore, it tends to decrease the electron density on oxygen.

Because of the delocalization of the negative charge in the benzene ring, the phenoxide ions are generally more stable than the alkoxide ions. Phenols, as a result, are more acidic in nature than alcohols. In the case of the substituted phenols, the acidity decreases if there is an electron-donating group which is attached to the ring when the acidity increases in case of the electron-withdrawing group.

4. Chirality of Phenols

Phenols exhibit the property of chirality within their molecules, for example, in catechin. This chirality is because of the absence of a planar and axial symmetry in the molecule of phenol.

FAQ (Frequently Asked Questions)

1. What is Phenol?

Phenol is well known as carbolic corrosive and is a sweet-smelling natural compound. Being an unpredictable white crystalline strong, it is used in view of the capacity of causing compound consumption. Phenol is a vital material which is used as a part of different mechanical systems and is considered as a forerunner to several valuable mixes and materials. Phenol and its concoction results are essential for the generation of epoxies, bakelite, nylon, polycarbonates, cleansers, herbicides, like phenoxy herbicides, and pharmaceutical medications.

Phenol includes a liquor bonding that is not just skilled to figure an exceptionally strong hydrogen bond along with different particles; yet, this bonding adds to phenol's nature towards the polar substances. As a polar atom, phenol is soluble in water and shows its linkage and holding capacity. However, the physical state of the phenol is shown in a dreary shape. However, at room temperature, the strong phenol is found in white colour with a sweet smell.

2. What is the Chemical Formula of Phenol?

Phenol is an aromatic organic compound that has a molecular formula C₆H₅OH. It is a white-coloured crystalline solid which is volatile in nature.

The molecule of phenol contains a phenyl group (C₆H₅) which is bonded to a hydroxyl group (−OH).

It is mildly acidic in nature and requires careful handling because of its propensity to cause chemical burns.

3. Why is Phenol Acidic in Nature?

Phenol is acidic in nature because of its ability to lose the hydrogen ion for forming the phenoxide ions. In a phenol molecule, the sp² hybridised carbon atom of the benzene ring which is directly attached to the hydroxyl group acts in the form of an electron-withdrawing group. This sp² hybridized carbon atom of the benzene ring which is attached directly to the hydroxyl group has a higher electronegativity when compared to the hydroxyl group. Because of the higher electronegativity of this carbon atom when compared to the hydroxyl group attached, the electron density decreases in the oxygen atom. This decrease in the electron density, in turn, increases the polarity of the O-H bond and this results in the increase in the ionization of phenols. Therefore, the phenoxide ion is formed. The phenoxide ion that is formed is stabilized by the method of delocalization of the negative charge because of the resonance in the benzene ring present. Phenoxide ion has a greater stability when compared to phenols. In the case of phenol, the process of charge separation takes place during resonance.

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The resonance structures of these phenoxide ions explain the process of the delocalization of negative charge. In the case of substituted phenols, the acidity of phenols increases in the presence of an electron-withdrawing group. This is because of the stability of the phenoxide ion that is generated. The acidity of phenols increases further if these groups are attached at the ortho and para positions. This is because of the fact that the negative charge in the phenoxide ion is delocalized mainly at the ortho and para positions of the benzene ring which is attached. On the other hand, the acidity of phenols decreases in the presence of the electron-donating groups since they tend to prohibit the formation of the phenoxide ion.

4. What are Some of the Uses of Phenol?

Amongst the essential uses of phenol is the one which is found in the plastic assembling industry. Actually, two - third of the phenol making goes into this exclusive as imagining existence without plastics isn't possible. Apart from this, phenol is used as a part of the assembling phenolic saps such as bakelite. It is widely used as a part of the electrical switches and vehicles as well in the light of its capacity to sustain through the outrageous circumstances of high temperatures and resistance to power and several other chemicals. Apart from this, molecular science mentions its application in the form of nucleic acids from the tissue tests for several other examinations. Additionally to this, phenol is also used in the corrective industry in the making of skin creams, sunscreens, and hair colouring products. Being much economical in nature, phenol is also used as a part of several different enterprises. What's more, is that this makes phenol a standout amongst all the other adaptable natural mixes available in the world.