Question

Why are ethene and bromine an additional reaction?

Answer 1

First let us know that ethene is the most basic of the alkenes, which are chemical molecules with carbon-carbon double bonds. It's a combustible, colourless gas with a sweet flavour and odour. Bromine is an atomic number $35$ chemical elements. It's the third-lightest halogen, and at room temperature, it's a seething red-brown liquid that quickly evaporates to form a similar-coloured vapour.

Complete answer:
Ethene and bromine is an additional reaction. This is due to the fact that ethene is an alkene, a structure that is less stable than an alkane. Bromine, rather than replacing hydrogen, opens the double bond in ethene. Ethene has an alkane structure as a result of this.
It can further be explained that because ethene is an alkene with a double bond, the reaction between it and bromine is an additional reaction. Opening the double bond and reacting there is easier for new atoms than removing the hydrogen already connected and then bonding to it, which would be a substitution reaction.
The reaction between ethane and bromine forms dibromoethane which is a halogenoalkane.This reaction can be carried out at room temperature or at lower temperatures.l

Note:
It can be noted that during the reaction between ethene and bromine, two bromine atoms are added to ethane through the double bond of it. So, ethene reacts with one molecule of bromine and two atoms of bromine are added to the alkene molecule to form the alkyl halide compound which is dibromoethane in this case. This reaction also proves that alkenes are unsaturated organic compounds.