Question

Calculate the [H+]

and pH of a 0.000295 M
butanoic acid solution. Keep in mind that the a
of butanoic acid is 1.52×10-5

Answer 1

[H⁺]=6.696 x 10⁻⁵

pH = 4.174

Further explanation

Given

The concentration of 0.000295 M (2.95 x 10⁻⁴ M) butanoic acid solution

Required

the [H+] and pH

Solution

Butanoic acid is the carboxylic acid group. Carboxylic acids are weak acids

For weak acid :

`\tt [H^+]=√(Ka.M)`

Input the value :

[H⁺]=√1.52 x 10⁻⁵ x 2.95 x 10⁻⁴

[H⁺]=6.696 x 10⁻⁵

pH = - log [H⁺]

pH = - log 6.696 x 10⁻⁵

pH = 5 - log 6.696

pH = 4.174