Titration: Molarity of Acid or Base

Question

An aqueous solution of barium hydroxide is standardized by titration with a 0.166 M solution of perchloric acid.

If 22.2 mL of base are required to neutralize 13.4 mL of the acid, what is the molarity of the barium hydroxide solution?

Answer 1

Barium hydroxide = Ba(OH)₂

Perchloric acid = HClO₄

Ba(OH)₂ + 2 HClO₄ ==> Ba(ClO₄)₂ + 2H₂O ... balanced equation

moles HClO₄ present = 13.4 ml x 1 L/1000 ml x 0.166 mol/L = 0.00222 moles HClO₄

moles Ba(OH)₂ needed = 0.00222 mol HClO₄ x 1 mol Ba(OH)₂ / 2 mol HClO₄ = 0.00111 moles Ba(OH)₂

Since there are 22.2 mls Ba(OH)₂ and that is = 0.0222 L, the molarity is...

Molarity = 0.00111 moles/0.0222 L = 0.0500 M Ba(OH)₂