11. The Ka for benzoic acid is 6.5 × 10–5. Calculate the pH of a 0.10 M benzoic acid solution.

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dsdrajlin dsdrajlin · Answer 1 · 2020-01-17T04:35:42+01:00

Answer:

2.6

Explanation:

Benzoic acid is a weak acid that dissociates according to the following equation.

C₆H₅COOH(aq) ⇄ C₆H₅COO⁻(aq) + H⁺(aq)

We can calculate the equilibrium concentration of H⁺ using the following expression.

[H⁺] = √(Ka × Ca)

where,

Ka is the acid dissociation constant

Ca is the initial concentration of the acid

[H⁺] = √(6.5 × 10⁻⁵ × 0.10) = 2.5 × 10⁻³

The pH is

pH = -log [H⁺] = - log 2.5 × 10⁻³ = 2.6

okpalawalter8 okpalawalter8 · Answer 2 · 2022-03-25T13:16:37+01:00

The pH value of a 0.10 M benzoic acid solution is mathematically given as

[C6H5COOH] = 0.06294 M.

Question Parameters:

The Ka for benzoic acid is 6.5 × 10–5.

Generally, the equation for the Chemical Reaction is mathematically given as

C6H5COOH(aq) ---><---- H⁺(aq) + C6H5COO⁻

Therefore

C6H5COOH= 0,063 M - x.

Ka = [H⁺] · [C6H5COO⁻] / [C6H5COOH].

0,000063 = x^2 / 0,063 M - x.

x = 0,00006 M

In conclusion

[C6H5COOH] = 0,063 M - 0,00006 M. [C6H5COOH]

[C6H5COOH] = 0,06294 M.