To solve this problem, we need to find the amount of
Mg(OH)2 needed to neutralize the
HCl contained in the gastric juice produced in a day, and then calculate how many tablets this corresponds to.
First calculate the molar mass of
Mg(OH)2,
Molar mass of
Mg(OH)2=Mg+2×(O+H2)=24+2×(16+2)=24+2×18=60g/‌mol
Let's determine the total amount of
HCl produced:
Total amount of
HCl= Concentration of
HCl× Volume of gastric juice
=3.0g/L×2.5L=7.5g.
Next, compute the molar mass of
HCl :
From the equation, 1 mole of
Mg(OH)2 reacts with 2 moles of
HCl, so moles of
Mg(OH)2 needed will be half the number of moles of
HCl :
Moles of
Mg(OH) _ 2 required
Calculate the mass of
Mg(OH)2 required:
Mass of
Mg(OH)_2= Moles of
Mg(OH)_2× Molar Mass of
Mg(OH)_2=0.10275‌mol×60g∕mol=6.165g.
Each antacid tablet contains
600‌mg=0.6g of
Mg(OH)2. The number of tablets needed is:
Since you can't typically use a fraction of a tablet in practical terms, this would be rounded to: 10 tablets, matching option A.