Chapter 21, Problem 98A

Interpretation Introduction

Interpretation:

The structure, history of development and use of tetraethyllead needs to be discussed and the reason for discontinuation of its use in United States needs to be explained. Also, whether it is still in use elsewhere in the world as a gasoline additive should be determined.

Concept introduction:

Hydrocarbons make good wide variety of fuels and consumer goods as their covalent bonds store large amount of energy, on burning the molecule a large amount of energy is released.

Explanation of Solution

Tetraethyllead is an organometallic compound in which metal, lead (Pb) is attached by four ethyl groups (-CH₂CH₃). The structure of the molecule is:

It was first found in 1920s, synthesized by the action of ethyl chloride on a powdered alloy of lead.

This compound was used in gasoline as a chief antiknock agent in car engines.

In engines, on heating the bonds between ethyl groups and lead breaks down and forms lead atom which on combustion forms lead oxide (PbO). The use of tetraethyllead was discontinued once it was found to be poisoning due to toxic metal lead in the compound.

Yes, it is still in use elsewhere in the world as a gasoline additive as it is used in gasolines for planes.