[Chem Nerd12321]

Magnesium Carbonate, MgCO3, is used in indigestion tablets as it reacts with and neutralizes stomach acids. The equation for the reaction between MgCO3 and HCl is shown below:

MgCO3(aq) + 2HCl(aq) ---> MgCl2(aq) + CO2(g) + H2O(l)

... and so the active constituent is the carbonate dianion, CO3(^2-), with Mg(^2+) being an inert counter ion...

CO3(^2-)(aq) + 2H+(aq) ----> CO2(g) + H2O(l)

Some tablets also contain aluminium hydroxide, which acts in a similar way...

Al(OH)3(aq) + 3HCl(aq) ---> AlCl3(aq) + 3H2O(l)

... and so the active constituent is the hydroxide anion, with Al(^3+) being an inert counter ion...

HO-(aq) + H+(aq) ---> H2O(l)

The Gaviscon Extra Strength brand contains 0.0749 g of CO3(^2-) and 0.105 g of HO- in each tablet.

(I) What mass of Mg(2+) is present in each tablet? Show your reasoning/Calculation. (10 marks)




(ii) What mass of Al(^3+) is present in each tablet? Show your reasoning/Calculation. (10 marks)




(iii) What total volume of 0.5 M HCl (in cm^3) is required to react with the MgCO3 and the Al(OH)3 present in one tablet? Show your reasoning/Calculation. (20 marks)