Mass of antacid in sample: 1.5004 g
Antacid tablet: 1.6080 g
Composition of antacid:
Aluminum hydroxide: 160 mg
Magnesium carbonate: 105 mg
Molarity of EDTA: 0.01000 M
Pipet a 10.00 mL aliquot of the antacid sample solution to a 125mL of Erlenmeyer flask followed by adding about 10 mL of thebicarbonate-carbonate buffer solution (pH 10.0 ± 0.1). Add about 3mL of triethanolamine (TEA) and swirl the mixture for 2 min. toenhance the formation of Al-triethanolamine complex and to mask theAl-EDTA complexation. Set the solution aside until the turbidsolution becomes mostly clear for easy observation of endpoint. Add5 drops of Calmagite indicator and mix well. The solution shouldappear wine red color in this moment.Direct-titrate the solutionwith standard EDTA solution until the color changes to pure blue atthe endpoint. The used volume of EDTA was 6.00ml. Hence, in thisprotocol quick titration will give an ideal result.
Compute the millimoles and weights of magnesium in theantacid sample solution and in the tablet.
