Question

A barium hydroxide solution is prepared by dissolving 2.29 g of Ba(OH)2 in water to make 46.6 mL of solution. What is the concentration of the solution in units of molarity?
Concentration: 0.287 M

The barium hydroxide solution is used to titrate a perchloric acid solution of unknown concentration. Write a balanced chemical equation to represent the reaction between barium hydroxide and perchloric acid.
Chemical Equation:

If 25.5 mL of the barium hydroxide solution was needed to neutralize a 8.99 mL aliquot of the perchloric acid solution, what is the concentration of the acid?
Concentration:

Answer 1

Answer:

0.287 M

Ba(OH)₂ + 2 HClO₄ ⇒ Ba(ClO₄)₂ + 2 H₂O

1.62 M

Explanation:

Step 1: Calculate the concentration of Ba(OH)₂

We will use the following expression.

[Ba(OH)₂] = mass Ba(OH)₂/ molar mass Ba(OH)₂ × liters of solution

[Ba(OH)₂] = 2.29 g/ 171.34 g/mol × 0.0466 L = 0.287 M

Step 2: Write the balanced neutralization equation

Ba(OH)₂ + 2 HClO₄ ⇒ Ba(ClO₄)₂ + 2 H₂O

Step 3: Calculate the reacting moles of Ba(OH)₂

25.5 mL of 0.287 M Ba(OH)₂ react.

0.0255 L × 0.287 mol/L = 7.32 × 10⁻³ mol

Step 4: Calculate the reacting moles of HClO₄

7.32 × 10⁻³ mol Ba(OH)₂ 2 mol HClO₄/1 mol Ba(OH)₂ = 0.0146 mol HClO₄

Step 5: Calculate the concentration of HClO₄

0.0146 moles of HClO₄ are in 8.99 mL of solution.

[HClO₄] = 0.0146 mol/0.00899 L = 1.62 M