Mg + 2 HCl → MgCl₂ + H₂

is a single displacement reaction. Here's why:

* Single Displacement: In this type of reaction, a more reactive element displaces a less reactive element from a compound.

* In this case: Magnesium (Mg) is more reactive than hydrogen (H). It displaces hydrogen from hydrochloric acid (HCl) to form magnesium chloride (MgCl₂) and hydrogen gas (H₂).

Let me know if you'd like to explore other types of chemical reactions!