Balance this equation:
Mg + HCl —> MgCl2 + H2
In order to balance this equation, we need to ensure that the number of atoms of each element is equal on both sides of the equation.
Mg + 2 HCl → MgCl2 + H2
By adding a coefficient of 2 in front of HCl, we ensure that there are 2 atoms of hydrogen and 2 atoms of chlorine on the right side of the equation. This balancing of the equation ensures that both sides have the same number of atoms of each element involved.