Question

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.

Answer 1

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