Q.Bakelite is prepared by the condensation of phenol with formaldehyde. Name the linear intermediate formed before cross-linking, and describe the role formaldehyde plays in forming the final resin.

When phenol is condensed with a LIMITED amount of formaldehyde under acidic catalysis, the reaction stops at a linear, low-molecular-weight, still-fusible prepolymer called novolac (a base-catalysed, formaldehyde-excess route instead gives a partially cross-linked prepolymer called resole). In either case, this intermediate still carries reactive $-\text{CH}_2\text{OH}$ groups and open, unreacted ring positions. On curing (heating, usually with additional formaldehyde as a cross-linking agent and a hardener), formaldehyde's role shifts from simply extending single chains to actively BRIDGING separate chains: it reacts with the reactive sites on neighbouring novolac/resole chains to form methylene ($-\text{CH}_2-$) bridges linking many phenol rings together in three dimensions, …

Separate bakelite's formation into two distinct stages -- linear prepolymer formation, then cross-linking -- and id …

Treating prepolymer formation and cross-linking as the same single step; forgetting that it is specifically the CROSS-LINKING stage, not the initial condensati …