Solving a problem in chemistry section 11 point 85

85. The sample of magnesium in the air and burned ash was dissolved in 60 ml of 1 M hydrochloric acid. On neutralization of the spent solution 12 ml of 1 M sodium hydroxide solution. After adding excess alkali solution to boil, and while the separated gas is passed into the flask with 12 mL of 1 M hydrochloric acid. On neutralization of the solution in the flask spent 6 ml of 1 M sodium hydroxide solution. Determine the weight of the sample of magnesium and ash composition.