Answer to Question #348769 in Chemistry for Remo

Question

A solution of Ba(OH)2 was standardized against 0.1016 g of primary standard benzoic acid C6H5COOH Calculate the concentration of if the end point was 20.89 mL.

Answer 1

Solution:

Balanced chemical equation:

Ba(OH)₂ + 2C₆H₅COOH → (C₆H₅COO)₂Ba + 2H₂O

According to stoichiometry:

Moles of Ba(OH)₂ = Moles of C₆H₅COOH / 2

or:

2 × Molarity of Ba(OH)₂ × Volume of Ba(OH)₂ = Mass of C₆H₅COOH / Molar mass of C₆H₅COOH

Therefore,

Molarity of Ba(OH)₂ = (Mass of C₆H₅COOH) / (2 × Volume of Ba(OH)₂ × Molar mass of C₆H₅COOH)

Molarity of Ba(OH)₂ = unknown

Mass of C₆H₅COOH = 0.1016 g

Volume of Ba(OH)₂ = 20.89 mL × (1 L / 1000 mL) = 0.02089 L

Molar mass of C₆H₅COOH = 122.12 g mol⁻¹

Thus,

Molarity of Ba(OH)₂ = (0.1016 g) / (2 × 0.02089 L × 122.12 g mol⁻¹) = 0.01991 mol L⁻¹

The molarity of Ba(OH)₂ solution is 0.01991 M

Answer: The molar concentration of Ba(OH)₂ solution is 0.01991 M