Answer: The balanced chemical equation is given below.
Step-by-step explanation:
Mg(OH)2 is a base and HCl is an acid.
When a base reacts with an acid, it leads to the production of a salt with the release of water molecule. This reaction is known as neutralization reaction.
The balanced chemical equation for the reaction follows:

By Stoichiometry of the reaction:
1 mole of magnesium hydroxide reacts with 2 moles of hydrochloric acid to produce 2 moles of magnesium chloride and 2 moles of water molecule.