Solution :-
lets first calculate the moles of the EDTA
moles of EDTA = 0.0105 mol per L * 0.04555 L = 0.0004783 mol
mole ratio of the EDTA to Mg2+ is 1 : 1
so the moles of Mg^2+ = 0.0004783 mol
mass of Mg^2+ = moles * molar mass
                      Â
=0.0004783 mol * 24.305 g per mol
                     Â
= 0.01163 g Mg
% of Mg^2+ = (mass of Mg^2+ / mass of sample )*100 %
                   Â
= (0.01163 g / 0.2600 g)*100%
                   Â
= 4.47 %
now l;ets calculate the weight percent of the Mg in the
sample
% Mg = ((4*24.305 g)/365.3 g)*100%
        = 26.61 %
