Final answer:
The reaction Mg + 2 HCl → MgCl₂ + H₂ is an example of a single-replacement reaction where magnesium replaces hydrogen in hydrochloric acid, producing magnesium chloride and hydrogen gas.
Step-by-step explanation:
The reaction between Mg and 2 HCl is an example of a single-replacement reaction. In this type of reaction, an element (in this case, magnesium, Mg) replaces another element in a compound, resulting in a new element and a new compound as products. Here, magnesium replaces hydrogen in hydrochloric acid (HCl), yielding magnesium chloride (MgCl2) and hydrogen gas (H2).
To write the balanced chemical equation for a single-replacement reaction like this, we first ensure that the number of atoms for each element is the same on both sides of the equation. In the given reaction:
Mg(s) + 2 HCl(aq) → MgCl2(aq) + H2(g),
we have one magnesium atom on both sides, two chlorine atoms on both sides, and two hydrogen atoms on both sides, confirming that the reaction is balanced.