Question

Benzoic acid, C6H5COOH, is another derivative of benzene. The pH of an aqueous solution of benzoic acid at 298 K is 2.95. Determine the concentration of hydroxide ions in the solution,

Answer 1

Answer:

[OH⁻] = 8.91x10⁻¹²M

Explanation:

In aqueous solutions, the [OH] and [H⁺] are associated in the equation of hydrolisis of water:

1x10⁻¹⁴ = [OH⁻] [H⁺]

With pH, we can solve for [H⁺] and obtain, the [OH⁻] using this equation:

pH = -log [H⁺]

[H⁺]= 10^-pH

[H⁺] = 1.122x10⁻³M

1x10⁻¹⁴ = [OH⁻] [1.122x10⁻³M]

[OH⁻] = 8.91x10⁻¹²M