What volume of 0.140 M HCl is needed to neutralize 2.93 g of Mg(OH)2

Answer 1

Mg(OH)2 + 2 HCl ==> MgCl2 + 2H2O
mols Mg(OH)2 = grams/molar mass = ?
mols HCl = twice that (from the coefficients in the balanced equation.
Then molarity HCl = mols HCl/L HCl.. You know molarity and mols, solve for L. Convert to mL if needed.