A 0.2527-g sample of a mixture of Mg(OH)2 and Al(OH)3 was treated with 50.00 mL of 0.225 mol L?1 HCl(aq). The resulting solution required 13.73 mL of 0.176 mol L?1 NaOH(aq) to neutralize the excess, unreacted HCl. What was the percentage by mass of Mg(OH)2 in the original sample? [Hint: When Mg(OH)2 or Al(OH)3 reacts with HCl(aq), the products are a chloride salt, water and CO2(g). Assume that all of the CO2(g) leaves the solution without reacting.]