Answer:
An addition reaction
Step-by-step explanation:
In an addition reaction, two or more molecules come together to form a single product, for example,
C₂H₂ + 2Cl₂ ⟶ C₂H₂Cl₄
This reaction consists of two successive additions. The product of the first reaction becomes a reactant and adds a second molecule of Cl₂ to form C₂H₂Cl₄
C₂H₂ + Cl₂ ⟶ C₂H₂Cl₂
C₂H₂Cl₂ + Cl₂ ⟶ C₂H₂Cl₄
C₂H₂ + 2Cl₂ ⟶ C₂H₂Cl₄