The reaction of ethene with bromine is ……… reaction.

Answer

To determine the type of reaction that occurs when ethene reacts with bromine, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The reactants in this reaction are ethene (C2H4) and bromine (Br2).

2. **Understand the Structure of Ethene**:
- Ethene has a double bond between the two carbon atoms, represented as CH2=CH2. The double bond consists of one sigma (σ) bond and one pi (π) bond.

3. **Recognize the Nature of Bromine**:
- Bromine (Br2) is a diatomic molecule that can act as an electrophile due to the polarizability of its bond. When it approaches the double bond of ethene, the π bond can induce a dipole in the Br2 molecule.

4. **Mechanism of the Reaction**:
- The π bond in ethene acts as a nucleophile and attacks one of the bromine atoms. This results in the breaking of the Br-Br bond and the formation of a bromonium ion intermediate.
- The other bromine atom, which has a partial negative charge, can then attack the carbocation formed from the ethene, resulting in the addition of bromine across the double bond.

5. **Final Product**:
- The final product of this reaction is 1,2-dibromoethane (C2H4Br2), where bromine atoms are added to each of the carbon atoms that were originally part of the double bond.

6. **Type of Reaction**:
- Since the reaction involves the addition of bromine to the double bond of ethene, it is classified as an **electrophilic addition reaction**.

### Conclusion:
The reaction of ethene with bromine is an **electrophilic addition reaction**.

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