Respuesta :

transitionstate
Milk of Magnesia is an antacid suspension containing 7% to 8.5% Magnesium Hydroxide [Mg(OH)₂]. Magnesium Hydroxide normally ionizes as follow,

                           Mg(OH)₂     →     Mg²⁺   +   2 OH⁻

Result:
           So, the negative Ion found in Milk of Magnesia is Hydroxyl Ion (OH⁻).