Question

Why is lead compound added to petrol?

Answer 1

Hint: If something is added to petrol it basically improves engine performance. Lead compounds reduce combustion when burnt and help with wear and tear and valve seat within the motor but that leads to some undesirable side effects.

 Complete step by step answer:
-There are major advantages of leaded gasoline. A very poor-quality natural gasoline having a very low octane rating can be easily and cheaply converted into a higher-octane product. -Leaded gasoline raises the octane rating of the fuel at a very low cost which is more desirable for compact high-power engines.
-The octane rating is a measure of the ability of a fuel to avoid knocking. Knocking occurs when fuel is prematurely ignited in the engine’s cylinder, results in low-efficiency and damaging the engine. This is due to the presence of oxygenate in the fuel that prevents knocking by adding oxygen to the fuel. We call this oxygenate an octane.
-Tetraethyl lead provides octane to gasoline, thereby preventing engine knock. There are other octane providers, such as benzene and ethanol, but due to low production cost, lead is more preferred. It is added to petrol to make it burn smoothly in motor vehicles.

Therefore, lead compound is added to petrol.

Note:
Longer exposure to the lead, results in lead poisoning which could further cause chronic degenerative diseases, such as anaemia, low IQ, hypertension, nerve damage, behavioural disorder and cardiovascular disease. Thus, it got banned in most of the countries.