Which compound is added to Petrol for preventing knock-of the Engines?

Question

In the chemical process of Vulcanization, with which element is the natural rubber heated to make it usable by improving its properties ?

Answer 1

Lead component is added to Petrol to preventing knock-of the Engines.

Answer 2

Tetraethylplumbane another name is Lead tetraethyl mixed with gasoline (petrol) to preventing knock-of the Engines.

The Skeletal Formula is