1. The problem statement, all variables and given/known data If 0.12 g of magnesium hydroxide Mg(OH)2 is dissolved in sufficient water to make 500. mL of solution, what is the hydronium ion concentration in the solution? (Assume that all of the magnesium hydroxide dissolves.) 2. Relevant equations pH = -log [OH-] pOH = -log [H3O+] 3. The attempt at a solution I got 5 * 10^-12: Mg(OH)2 --> Mg2+ + 2OH- [OH-] = 2.058 * 10^-3 M pOH = 2.6852 then pH = 14 - pOH = 11.31 [H3O+] = 10^-11.30 = 5*10^-12 is this the right method, is there an easier way?