Final answer:
The best method for magnesium analysis is gravimetric analysis, which involves precipitation and weighing the magnesium compound to determine its concentration. The precision of this method is high with results rounded to one significant digit.
Step-by-step explanation:
The best method to perform magnesium analysis is dependent on the context and the precision required. A common approach to determine the concentration of magnesium, especially in the context of precipitations, is gravimetric analysis. In gravimetric analysis, the magnesium in a sample is precipitated and weighed to determine its concentration. For example, when treating a mixture containing MgSO4 with Ba(NO3)2, the magnesium sulfate reacts to form solid BaSO4. The mass of the precipitate is used to calculate the mass percent concentration of MgSO4 in the original mixture. This method is attractive due to its high precision, as the final result is rounded to one significant digit, which is limited by the certainty of the Ksp. Similarly, for complexation titration involving Mg2+ with EDTA, an indicator is used to show the endpoint, yielding quantitative results for magnesium content.