Q.Distinguish between low density polythene (LDPE) and high density polythene (HDPE) in terms of the polymerization conditions used, chain structure, and physical properties.

LDPE is made by free-radical addition polymerization of ethene at high pressure ($1000$--$2000$ atm) and high temperature. During chain propagation, the growing radical occasionally abstracts a hydrogen from its own backbone ('backbiting'), creating short and long branch points along the chain; these branches prevent the chains from packing closely, giving LDPE a lower density and a soft, flexible material used for bags and film. HDPE is instead made at low pressure and moderate temperature using a Ziegler-Natta catalyst ($\text{TiCl}_4$/$\text{Al(C}_2\text{H}_5)_3$), which polymerises ethene by a coordination mechanism that adds monomer units in a strictly linear fashion, essentially without branching. The resulting straight chains pack much more closely …

Compare the two manufacturing routes (free-radical high pressure versus Ziegler-Natta catalysed low pressure) and trace how each affects chain b …

Assuming both forms are made by the identical process; reversing which form (LDPE vs H …