A 5.00 mL sample of barium hydroxide is titrated to the phenolphthalein endpoint using hydrochloric acid. the five mL sample requires 18.02 mL of 0.0873 M HCl solution to reach the endpoint. what is the concentration of the Ba(OH)2 solution?
Ba(OH)2 (aq) + 2 HCl (aq) ------> BaCl2 (aq) + 2H2O (l)