An aqueous solution of barium hydroxide is standardized by titration with a 0.103 M solution of perchloric acid. If 21.0 mL of base are required to neutralize 12.3 mL of the acid, what is the molarity of the barium hydroxide solution

0.0302M is molarity of the barium hydroxide solution.

Explanation:

The titration of Ba(OH)2 with HClO4 is:

Ba(OH)2 + 2HClO4 → 2H2O + Ba(ClO4)2

Where 2 moles of perchloric acid reacts per mole of barium hydroxide

First, we need to obtain the moles of the acid used in the titration. Then, convert these moles to moles of barium hydroxide using the chemical equation and, with the volume, we can obtain the molarity of the barium hydroxide solution:

Moles perchloric acid:

12.3mL = 0.0123L * (0.103mol/L) = 0.00127 moles of perchloric acid

Moles Barium hydroxide:

0.00127 moles of perchloric acid * (1 mole Ba(OH)2 / 2 moles HClO4) =

6.33x10⁻⁴ moles Ba(OH)2

Molarity -Moles Ba(OH)2 per liter of solution-:

6.33x10⁻⁴ moles Ba(OH)2 / 0.0210L =