Question

The correct statement regarding X and Y in the following set of reactions is

• A. X is HDP and Y is LDP
• B. X is LDP and Y is HDP
• C. X is used in the preparation of flexible pipes and Y is used in manufacturing squeeze bottles
• D. X is used in insulation of electricity carrying wires, Y is used in manufacturing of bottles

Hint:

Polymerization of Ethene: - Low-Density Polyethylene (LDP or LDPE): Formed by free-radical polymerization at high pressure (1000-2000 atm) and high temperature (350-570 K) using traces of oxygen or a peroxide initiator (like benzoyl peroxide). It has a branched structure, leading to lower density and flexibility. Uses: Squeeze bottles, toys, flexible pipes, insulation, packaging films. - High-Density Polyethylene (HDP or HDPE): Formed by coordination polymerization using Ziegler-Natta catalyst (e.g., triethylaluminium and titanium tetrachloride) at lower temperature (333-343 K) and pressure (6-7 atm). It consists of linear chains, leading to higher density and rigidity. Uses: Buckets, dustbins, bottles, pipes (more rigid), housewares.

Answer 1

The Correct Option is B

The reactions shown are polymerization processes of ethene (\( \text{CH}_2=\text{CH}_2 \)) to form polyethylene.
Reaction to form Y: Ethene \( \xrightarrow{(\text{C}_2\text{H}_5)_3\text{Al} / \text{TiCl}_4, \, 333-343 \, \text{K}, \, 6-7 \, \text{atm}} \) Y The catalyst system \( (\text{C}_2\text{H}_5)_3\text{Al} / \text{TiCl}_4 \) is a Ziegler-Natta catalyst.
Polymerization of ethene using Ziegler-Natta catalysts occurs at relatively low temperatures and pressures and leads to linear polyethylene chains with high density.
This product is High-Density Polyethylene (HDP or HDPE).
So, Y is HDP.
Reaction to form X: Ethene \( \xrightarrow{(\text{C}_6\text{H}_5\text{COO})_2, \, 350-570 \, \text{K}, \, 1000-2000 \, \text{atm}} \) X The catalyst \( (\text{C}_6\text{H}_5\text{COO})_2 \) is benzoyl peroxide, which is a free-radical initiator.
Polymerization of ethene via a free-radical mechanism at high temperatures and very high pressures leads to branched polyethylene chains with low density.
This product is Low-Density Polyethylene (LDP or LDPE).
So, X is LDP.
Therefore, X is LDP and Y is HDP.
This matches option (2).
Let's check the uses mentioned in other options: - LDP (X): It is flexible and used for squeeze bottles, packaging films, flexible pipes, insulation for wires.
- HDP (Y): It is more rigid and has higher tensile strength.
Used for making buckets, dustbins, bottles, pipes (can be rigid).
Option (3): "X (LDP) is used in the preparation of flexible pipes and Y (HDP) is used in manufacturing squeeze bottles".
LDP is used for flexible pipes.
Squeeze bottles are typically made from LDP due to its flexibility.
HDP is used for more rigid bottles.
So this statement is partially correct for X, but Y for squeeze bottles is less typical (HDP is for stiffer bottles).
Option (4): "X (LDP) is used in insulation of electricity carrying wires, Y (HDP) is used in manufacturing of bottles".
LDP is indeed used for wire insulation.
HDP is used for manufacturing bottles (e.
g.
, milk jugs, detergent bottles).
This statement appears correct regarding uses.
However, the primary question is about identifying X and Y.
X is LDP, Y is HDP.
This is definitively option (2).