What are the names of the reactants in this equation?

Mg (s) + 2HCl (aq) --> MgCl2 (aq) +H2 (g)

magnesium(solid)

hydrochloric acid (solution)
magnesium chloride (solution)
hydrogen (gas)

To determine the reactants in a chemical equation, you need to identify the substances that are present before the reaction occurs. In this equation:

Mg (s) + 2HCl (aq) --> MgCl2 (aq) + H2 (g)

The reactants are shown on the left side of the arrow. In this case, the reactants are:

1. Mg (s): This stands for magnesium, which is in solid state (s).
2. HCl (aq): This stands for hydrochloric acid, which is in aqueous state (aq).

Therefore, the reactants in the equation are magnesium (Mg) in solid form and hydrochloric acid (HCl) in aqueous form.