6 - Organic Chemistry I

Question 1

Describe what happens to the σ and π bonds in ethene when it undergoes an addition reaction:

Answer 1

-σ remains because it is stronger, but π breaks because it is weaker
-breaking π results in carbocation intermediate forming

Question 2

Suggest why high temperatures are required for cracking:

Other than to speed up the reaction

Answer 2

to overcome the high activation energy (needed to break the C-C and C-H bonds)

Question 3

What is cracking?

Answer 3

use of high temperatures/catalysts to break longer hydrocarbon chains into shorter alkanes and alkenes

Question 4

What is one risk of this experiment? Explain how to amend it:

other than the ill-fitting bung

Answer 4

-suck back
-remove delivery tube from water before stopping heating

Question 5

What is produced when ethene reacts with bromine water?

Answer 5

-1,2-dibromoethane (from electrophilic addition)
-however the major product is 2-bromoethanol since the water gets involved in the reaction