J.R. S. answered 04/27/21
Ph.D. University Professor with 10+ years Tutoring Experience
Ca(OH)2 + 2CH3COOH ==> Ca(CH3COO-)2 + 2H2O
moles CH3COOH used = 100 ml x 1 L / 1000 ml x 0.10 mol/L = 0.0100 moles CH3COOH
moles Ca(OH)2 present = 0.0100 mol CH3COOH x 1 mol Ca(OH)2 / 2 mol CH3COOH = 0.005 mol Ca(OH)2
Molarity of Ca(OH)2 = 0.005 mol / 0.200 L = 0.0250 M