ANS:A - Straight run gasoline

Among the categories of gasoline listed, straight run gasoline typically has the highest lead susceptibility. Here's why:

1. Lead Susceptibility:
   • Lead susceptibility refers to the tendency of gasoline to form lead deposits in the engine when leaded gasoline (containing tetraethyl lead) is used.
   • Straight run gasoline, which is obtained directly from the fractional distillation of crude oil, tends to have lower octane ratings and can readily form lead deposits when lead additives are used.
2. Types of Gasoline:
   • Straight Run Gasoline: Produced by simple distillation of crude oil, it contains a mix of hydrocarbons and is relatively less refined.
   • Platinum Reformed Gasoline: Produced by reforming processes that increase its octane rating, making it less prone to knocking.
   • Catalytically Cracked Gasoline: Produced by catalytic cracking of heavier hydrocarbons, improving its octane rating and performance.
   • Polymer Gasoline: Produced by polymerization processes, often for specialized applications like synthetic rubber production.
3. Lead Deposits:
   • Lead compounds in gasoline were historically used as octane enhancers but led to harmful emissions and engine deposits.
   • Straight run gasoline, being less refined and having lower octane ratings, tends to have higher lead susceptibility compared to more refined and higher octane gasoline types like reformed and cracked gasolines.