MCQ Detailed View

Bakelite is a synthetic plastic formed when phenol reacts with formaldehyde in the presence of a dilute acid or base catalyst. This reaction is an example of condensation polymerization, a process in which smaller molecules combine to form a large polymer while eliminating a small byproduct, usually water.

The mechanism begins with the substitution of hydrogen atoms in phenol by hydroxymethyl groups (–CH₂OH) when formaldehyde is added. These substituted phenols then undergo further reactions, where the –CH₂OH groups condense with other phenolic groups, releasing water molecules in the process. Step by step, long polymer chains are formed. Upon further condensation, a hard and cross-linked three-dimensional structure develops, which is known as Bakelite.

Bakelite was invented by Leo Baekeland in 1907 and is considered the first fully synthetic plastic. It is known for being hard, resistant to heat, non-conductive, and chemically stable. These properties made it one of the most useful materials of the early plastics industry.

The incorrect options help understand why condensation polymerization is the correct choice. Addition polymerization occurs in alkenes like ethene forming polyethylene, which is not the case here. Isomerization only rearranges structures without forming polymers. Hydrogenation is the addition of hydrogen across double bonds, which does not happen in this reaction.

Bakelite has many applications due to its durability and insulating properties. It is widely used in the manufacture of electrical switches, handles of household utensils, telephones, and automotive parts. It is also resistant to solvents, which makes it suitable for coatings and adhesives.

Thus, the reaction between phenol and formaldehyde to form Bakelite is classified as condensation polymerization, a key example in organic polymer chemistry.