J.R. S. answered 11/13/21
Ph.D. University Professor with 10+ years Tutoring Experience
Ca(OH)2 + 2HCl ==> 2H2O + CaCl2 ... balanced equation
moles HCl present = 75.0 ml x 1 L / 1000 ml x 0.0300 mol/L = 0.00225 mols HCl
moles Ca(OH)2 needed = 0.00225 mols HCl x 1 mol Ca(OH)2 / 2 mols HCl = 0.001125 mols Ca(OH)2
volume (in mls) of 0.016 M Ca(OH)2 = 0.001125 mols Ca(OH)2 x 1 L / 0.016 mol x 1000 ml/L = 70.3 mls