The balanced chemical equation for the reaction between magnesium hydroxide and hydrochloric acid is:

$$Mg(OH)_2(aq) + 2HCl(aq) → MgCl_2(aq) + 2H_2O(l)$$

From the equation, we can see that the products of the reaction are magnesium chloride $(MgCl_2)$ and water $(H_2O)$. Therefore, the salt formed when magnesium hydroxide is neutralized by hydrochloric acid is magnesium chloride.