Effects of sulphur in gasoline Which statement best describes the impact of sulphur compounds naturally present in gasoline on equipment and fuel quality?

Introduction / Context:
Sulphur occurs in crude-derived gasoline as a range of organosulphur compounds (e.g., mercaptans, sulfides, thiophenes). Even at low levels it influences corrosion risk, exhaust emissions, and the performance/longevity of aftertreatment systems (e.g., catalysts). Understanding these effects informs hydrotreating targets and fuel specifications.

Given Data / Assumptions:

• Gasoline contains minor sulphur species prior to deep desulfurisation.
• We assess broad qualitative impacts relevant to operations and quality.
• Legacy leaded-fuel notions are not to be conflated with modern practice.

Concept / Approach:
Sulphur compounds can be corrosive directly or form acids upon combustion (e.g., SO2/SO3 with moisture). They also poison catalysts and impair aftertreatment. Historically, sulphur reduces lead susceptibility (response to tetraethyl lead), not increases it, and it does not prevent gum; rather, oxidised sulphur species may contribute to instability. Therefore, the reliable, general statement is that sulphur leads to corrosion and is undesirable.

Step-by-Step Solution:

Verification / Alternative check:
Fuel standards progressively tightened sulphur limits (ppm levels) precisely to mitigate corrosion, emissions, and catalyst poisoning.

Why Other Options Are Wrong:

• Increases lead susceptibility: Historically the opposite trend; not applicable to unleaded eras.
• Decreases gum / Helps stabilisation: Sulphur does not enhance storage stability; antioxidants address gum, not sulphur.

Common Pitfalls:
Confusing sulfur's role with that of antioxidants or deposit control additives; also mixing historical leaded-fuel context with modern fuels.

Final Answer:
Leads to corrosion in fuel systems and exhaust aftertreatment