Answer to question 1
alkene halogenation reaction is a reaction in which dihalides such as cl2 added to a molecule after breaking the carbon to carbon double bond.
Answer to question 2
Answer to question 3
In both cases, addition of halogen across the double bond takes place.The reaction is called halogenation.
The addition of chlorine to but-1-ene results in the cleavage of the double bond and the product formed will be 1,2-dibromobutane.
Addition of bromine to pent-2-ene also results in the cleavage of double bond and 2,3-dibromo pentane results.
Answer to question 4