Fe + 2HCl → FeCl₂ + H₂

is a single replacement reaction. Here's why:

* Single Replacement: A single replacement reaction involves one element replacing another element in a compound.

In this case:

* Iron (Fe) is more reactive than hydrogen (H).

* Iron replaces hydrogen in hydrochloric acid (HCl), forming iron(II) chloride (FeCl₂) and releasing hydrogen gas (H₂).

Let's break down why it's not the other types:

* Synthesis: A synthesis reaction combines two or more reactants to form a single product. This is not the case here, as there are two products.

* Decomposition: A decomposition reaction breaks down a single reactant into two or more products. Again, this is not the case as we start with two reactants.