How many grams of Mg(OH)2 will be needed to neutralize 25 mL of stomach acid if stomach acid is 0.10 M HCl?

Answer 1

Bookkeeping:

volume (L) acid x concentration of acid = moles of acid

2 moles acid = 1 mole Mg(OH)2

Now you know the number of moles Mg(OH)2, convert to g Mg(OH)2 (if you do not know how to do this, ask)