Answer to Question #142250 in General Chemistry for Aida

Question

Which antacid product would you expect to be more effective at neutralizing acid per gram of the
active ingredient: Tums or milk of magnesia? Explain your reasoning with pertinent calculations.

Answer 1

Reactions:

CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O

Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O

M(CaCO₃) = 100 g/mol

M(Mg(OH)₂) = 56 g/mol

Two moles of HCl are used for one mole of antacid product in both reactions.

So, to neutralize of two moles of HCl less Mg(OH)₂ (56 g) are required as compared to 100 g of CaCO₃.

So, milk magnesia is more effective at neutralizing acid per gram of the active ingredient.