The balanced chemical equation for the reaction of manganese dioxide (MnO₂) with hydrochloric acid (HCl) is:

MnO₂ + 4 HCl → MnCl₂ + 2 H₂O + Cl₂

Here's what happens in the reaction:

* Manganese dioxide (MnO₂) reacts with hydrochloric acid (HCl) to produce:

* Manganese chloride (MnCl₂) - A soluble salt.

* Water (H₂O) - A byproduct of the reaction.

* Chlorine gas (Cl₂) - A yellowish-green gas.

Explanation:

* Oxidation-Reduction: This reaction is an example of an oxidation-reduction reaction. Manganese in MnO₂ is in a +4 oxidation state and is reduced to +2 in MnCl₂. Chloride ions in HCl are oxidized from -1 to 0 in chlorine gas.

* Balancing: To balance the equation, you need to make sure that the number of atoms of each element is the same on both sides of the equation. In this case, we need 4 HCl molecules to react with one MnO₂ molecule. This produces one MnCl₂ molecule, two H₂O molecules, and one Cl₂ molecule.