1.The percentage composition of Magnesium in Mg(PO4)2 can be calculated as follows- determine molar mass first :
• Molar mass of Mg₃(PO₄)₂ = 262.8582 g/mol
• Mass of Mg in Mg₃(PO₄)₂ = 24.305×3 = 72.915 g
2.Calculate Percentage composition of Mg
Percentage composition = (mass of element/mass of compound) * 100
=(72.915/262.8582)*100
=27.739%
≈27.74%
• This means that option D is correct, percentage composition of Mg inMg₃(PO₄)₂ = 27.74%