assumed that all of the initial Mg had reacted, therefore the total amount of Mg had transferred into Mg2+ in MgCl2
Molar mass for Mg is 24.31 g/mole and MgCl2 is 95.21 g/mole
--> nMgCl2= nMg = 24.31 g ÷ 24.31 g/mole = 1 mole
--> so the mass of MgCl2 = 1 mole × 95.21 g/mole = 95.21 g