Calculate the molarity of a solution of barium hydroxide if 18.15 ml of it is required for the titration of a 20.00 ml sample of a 0.2452 m hydrochloric acid solution.

The balanced equation for the reaction between Ba (OH) ₂ and HCl is as follows;

Ba (OH) ₂ + 2HCl - - - > BaCl₂ + 2H₂O

stoichiometry of Ba (OH) ₂ to HCl is 1:2

the number of HCl moles that have reacted - 0.2452 mol/L x (20.00 x 10⁻³ L)

number of HCl moles reacted = 0.004904 mol

2 mol of HCl reacts with 1 mol of Ba (OH) ₂

therefore 0.004904 mol of HCl reacts with - 1/2 x 0.004904 mol of Ba (OH) ₂

number of Ba (OH) ₂ moles in 18.15 mL - 0.002452 mol

Therefore number of Ba (OH) ₂ moles in 1000 mL - 0.002452 mol / (18.15 x 10⁻³ L)

molarity of Ba (OH) ₂ is = 0.1351 M