Ask Question
7 August, 04:44

The first disinfectant used by Joseph Lister was called carbolic acid. This substance now is known as phenol, C6H5OH (pKa = 9.90). What is the pH of a 0.10 M solution of phenol?

+3
Answers (1)
  1. 7 August, 04:59
    0
    5.5

    Explanation:

    Phenol is a weak acid that dissociates according to the following reaction.

    C₆H₅OH (aq) ⇄ C₆H₅O⁻ (aq) + H⁺ (aq)

    The pKa is 9.90. The acid dissociation constant (Ka) is:

    pKa = - log Ka

    Ka = antilog - pKa = antilog - 9.90

    Ka = 1.26 * 10⁻¹⁰

    Given the concentration of the acid, Ca = 0.10 M, and the Ka, We can find [H⁺] using the following expression.

    [H⁺] = √ (Ka * Ca)

    [H⁺] = √ (1.26 * 10⁻¹⁰ * 0.10)

    [H⁺] = 3.5 * 10⁻⁶ M

    The pH is:

    pH = - log [H⁺]

    pH = - log 3.5 * 10⁻⁶

    pH = 5.5
Know the Answer?
Not Sure About the Answer?
Find an answer to your question 👍 “The first disinfectant used by Joseph Lister was called carbolic acid. This substance now is known as phenol, C6H5OH (pKa = 9.90). What is ...” in 📗 Chemistry if the answers seem to be not correct or there’s no answer. Try a smart search to find answers to similar questions.
Search for Other Answers