Final answer:
The pH of a 0.1 M solution of acetic acid, with a pKa of 4.76, is calculated by finding the concentration of hydrogen ions produced by the dissociation of acetic acid. The concentration is determined to be 1.32 × 10−3 M. The pH of the solution is then found to be approximately 2.879.
Step-by-step explanation:
The question pertains to the calculation of the pH of a 0.1 M solution of acetic acid. Given that the pKa of acetic acid is 4.76, we can determine the pH by using the following equilibrium expression for acetic acid dissociation:
CH3COOH(aq) + H2O(l) ⇒ CH3COO−(aq) + H3O+ (aq)
Given that the acid dissociation constant (Ka) for acetic acid is 1.8 × 10−5, the concentration of hydrogen ions [H+] from the dissociation of acetic acid in a 0.1 M solution can be calculated. Solving the equation for the concentration of hydrogen ions gives [H+] = 1.32 × 10−3 M.
To find the pH, the negative logarithm of the hydrogen ion concentration is calculated:
pH = −log(1.32 × 10−3)
Thus, the pH of a 0.100 M solution of acetic acid is approximately 2.879.