Question 2 The structure of the product that is formed from the addition reaction between but-2-ene and chlorine, Cl₂, is: A - VCE - SSCE Chemistry - Question 2 - 2011 - Paper 1

To determine the product formed from the addition reaction between but-2-ene and chlorine, we must understand the mechanism of electrophilic addition. But-2-ene has a double bond between the second and third carbon atoms, making it a suitable candidate for addition reactions.

When chlorine reacts with but-2-ene, the double bond opens up, leading to the formation of a vicinal dihalide. The reaction proceeds as follows:

1. The double bond of but-2-ene attacks a chlorine molecule, resulting in the formation of a cyclic chloronium ion.
2. The other chlorine atom then attacks from the opposite side, leading to the addition of the chlorine atoms across the double bond.

Hence, considering the positioning of the carbons and the chlorines, the final structure that represents this addition reaction corresponds to option C in the provided images, where one chlorine atom is attached to the second carbon and another chlorine atom on the third carbon.