Final answer:
To balance the chemical equation Al + HCl → AlCl₃ + H₂, the correct set of coefficients is 2Al(s) + 6HCl(aq) → 2AlCl₃(s) + 3H₂(g), ensuring that the number of atoms for each element is the same on both sides of the equation.
Step-by-step explanation:
To balance the equation Al + HCl → AlCl₃ + H₂, we need to determine the correct set of coefficients that make sure the number of atoms for each element is equal on both sides of the reaction. First, we need to balance aluminum (Al) and then hydrogen (H) and chlorine (Cl). Starting with aluminum, for every mole of Al, we produce one mole of AlCl₃. However, there are three chlorine atoms in AlCl₃, which means we need 3 moles of HCl for each mole of Al to have enough chlorine atoms.
Now that we know the relationship between AlCl₃ and HCl, we can write a balanced equation as follows: 2Al(s) + 6HCl(aq) → 2AlCl₃(s) + 3H₂(g). Here, we've balanced aluminum by placing a coefficient of 2 in front of Al and AlCl₃, and we've balanced hydrogen and chlorine by using a coefficient of 6 in front of HCl and 3 in front of H₂.
Finally, always double-check your work to ensure that all elements are balanced and that the coefficients are in the simplest whole-number ratio.