Final answer:
The reaction of MgCl2 and F2 forming MgF2 and Cl2 is a synthesis (combination) reaction, where elements or compounds come together to form a single product.
Step-by-step explanation:
The reaction MgCl₂ + F₂ = MgF₂ + Cl₂ is an example of a synthesis or combination reaction. In this type of chemical reaction, elements or compounds combine to form a single new substance. Specifically, magnesium chloride and fluorine gas react to form magnesium fluoride and chlorine gas. This reaction is different from metal replacement or decomposition reactions, suggesting that the correct answer is D) Synthesis.