Arrange these petroleum fractions in decreasing order of their typical boiling ranges (highest boiling first): lubricating oil, diesel, petrol (gasoline), LPG.

Introduction:
Petroleum fractions are separated by boiling range. Ordering these fractions by decreasing boiling point reinforces understanding of atmospheric distillation cuts.

Given Data / Assumptions:

• Fractions considered: lubricating oil, diesel, petrol (gasoline), LPG.
• Decreasing order requested: highest boiling first.

Concept / Approach:
Heavier fractions boil at higher temperatures. Lubricating oil cuts are heaviest among the list, followed by diesel, then petrol, while LPG is the lightest with the lowest boiling range.

Step-by-Step Solution:
1) Identify heaviest fraction: lubricating oil (highest boiling).2) Next heavier: diesel.3) Then: petrol (gasoline).4) Lightest: LPG (lowest boiling).

Verification / Alternative check:
Typical boiling ranges confirm the order: lube oil > diesel > gasoline > LPG for atmospheric products.

Why Other Options Are Wrong:
Options b, c, d, e misplace gasoline or LPG relative to diesel and lubricating oil, contradicting distillation principles.

Common Pitfalls:
Confusing density with boiling range or assuming diesel boils below petrol; also mixing up LPG with light naphtha ranges.

Final Answer:
lubricating oil > diesel > petrol > LPG