Question

An antacid tablet weighing 15.468 g was dissolved in acid

& diluted to 500.0 mL. Then, a 25.00 mL aliquot of the soln was

made basic to ppt the aluminum as Al(OH)3.

The remaining magnesium req’d 16.50 mL of 1.042 x 10^-2 M

EDTA for titration. A second 25.00 mL aliquot was

withdrawn from the 500-mL flask & treated with 50.00 mL

of the EDTA. This soln was made basic & the x’ss EDTA back

titrated with 11.75 mL 5.597 x 10^-3 M MgCl2. Calc. % of

both Mg (24.30 g/mol) & Al (26.98 g/mol) in the sample.

Answer 1

Basic aluminum bicarbonate-carbonate in combination with magnesium basic carbonate, magnesium hydroxide, or magnesium trisilioate, or mixtures thereof,

said alcohol being a foodgrade di- or trihydroxy alcohol suitable for oral ingestion, wherein analysis of the codried combination yields a figure of from 30 to 60 weight percent for the sum of the aluminum hydroxide and magnesium hydroxide calculated as Al2 O3 and MgO and shows that there is present at least 0.3 mole of carbonate calculated as CO2 for each mole of Al2 O3, said codried combination being contained in the tablet in an amount of from 10 to 90 weight percent of the tablet.