Final answer:
The pH of a 0.0001 M HCl solution is 4. The pH of an acetic acid solution of the same concentration would be higher because acetic acid is a weak acid and dissociates less in solution than HCl.
Step-by-step explanation:
To calculate the pH of a 0.0001 M HCl solution, we can use the formula pH = -log[H+]. Since HCl is a strong acid, it fully dissociates in water. Therefore, the concentration of hydrogen ions [H+] is equal to the concentration of HCl, which is 0.0001 M. Plugging this into the formula gives us pH = -log(0.0001) = 4.
Comparing this to an acetic acid solution of the same concentration, we can see that the pH of the acetic acid solution would be higher because acetic acid is a weak acid.
While HCl fully dissociates, acetic acid only partially dissociates in solution, producing fewer hydrogen ions and resulting in a higher pH. For instance, a 0.100 M solution of acetic acid has a pH of approximately 2.879, indicating a lesser degree of ionization compared to HCl.