The polymer X-consists of linear molecules and is closely packed. It is prepared in the presence of trimethylaluminiumpropyl and titanium tetrachloride under low pressure. The polymer X is

The polymer X has the following characteristics:

- Consists of linear molecules

- Closely packed

- Prepared using trimethylaluminium and titanium tetrachloride (Ziegler-Natta catalyst) under low pressure

These are the defining features of High Density Polythene (HDPE):

- HDPE is prepared by coordination polymerisation of ethylene using Ziegler-Natta catalyst (combination of triethylaluminium/trimethylaluminium and TiCl$$_4$$) at low pressure (6-7 atm) and moderate temperature (333-343 K).

- The resulting polymer has a linear structure with very little branching, allowing the chains to pack closely together, resulting in high density (0.94-0.97 g/cm$$^3$$).

In contrast, Low Density Polythene (LDPE) is prepared by free radical polymerisation at high pressure (1000-2000 atm) and has a highly branched structure.

Therefore, polymer X is High Density Polythene.