Bakelite is obtained from phenol by reacting with (a) \(\left(\mathrm{CH}_{2} \mathrm{OH}\right)_{2}\) (b) \(\mathrm{CH}_{3} \mathrm{CHO}\) (c) \(\mathrm{CH}_{3} \mathrm{COCH}_{3}\) (d) HCHO

Phenol-formaldehyde resins are an important class of polymers that are widely used due to their strong mechanical properties and stability. Known as the first synthetic plastic, Bakelite is the most famous example of a phenol-formaldehyde resin. It was discovered by Belgian chemist Leo Baekeland in 1907. These resins are obtained by the reaction of phenol or substituted phenol with formaldehyde.

The process involves applying heat and pressure in the presence of a catalyst, which induces a condensation reaction that produces a highly cross-linked polymer matrix. This matrix is what gives these resins their durability, and it can be molded before it fully hardens, allowing various shapes and products to be created. This quality made Bakelite and other phenol-formaldehyde resins revolutionary during their introduction, as they could be used to produce a multitude of objects ranging from telephones to kitchenware.

A condensation reaction is a chemical process where two molecules combine with the loss of a smaller molecule, usually water or an alcohol. This is distinct from the addition reactions where atoms or groups are added to a molecule without the loss of any atom.

In the synthesis of Bakelite, the condensation reaction occurs between phenol and formaldehyde. The specific reaction involves the hydroxyl groups of phenol and the carbonyl group of formaldehyde, with the loss of water molecules to form –OH and –CH2– links. These reactions usually involve the formation of a new carbon-carbon bond, resulting in a larger molecular structure. The careful control of the reaction conditions can influence the polymer structure and thus the properties of the resulting resin. This reaction is also an example of a step-growth polymerization, where bonds form between monomers at any point in the chain, creating a network of interlinked chains.

Polymer chemistry is a branch of chemistry that focuses on the creation, characterization, and understanding of polymer molecules. Polymers are large molecules made up of repeating structural units, known as monomers, that are typically connected by covalent chemical bonds.

Within the context of polymer chemistry, there are several types of polymerization reactions, one of which includes the condensation polymerization discussed earlier. This type of reaction is key to creating many of the plastics and resins that are integral to modern society, such as polyesters, nylons, and of course, phenol-formaldehyde resins like Bakelite.

The physical properties of a polymer depend on the length of the polymer chains, the degree of cross-linking, and the molecular structure. These characteristics determine the plastic's tensile strength, flexibility, heat resistance, and other attributes. With this understanding of polymer chemistry, chemists and engineers can design and produce materials with tailor-made properties for specific applications.