Final answer:
Hydrochloric acid will have a lower pH than ethanoic acid at the same concentration due to its complete ionization in solution, resulting in a higher concentration of hydronium ions and a more acidic solution.
Step-by-step explanation:
Hydrochloric acid will have a lower pH compared to ethanoic acid with the same concentration. Hydrochloric acid (HCl) is a strong acid, meaning it is 100% ionized in solution, leading to a high concentration of hydronium ions, which results in a lower pH. In contrast, ethanoic acid is a weak acid and only partially dissociates in solution, meaning its concentration of hydronium ions will be lower than that of an equal concentration of hydrochloric acid, resulting in a higher pH.
The pH scale is logarithmic; thus, a strong acid like hydrochloric acid will cause a more significant shift in pH due to its higher concentration of hydronium ions compared to a weak acid like ethanoic acid at the same molarity. Therefore, hydrochloric acid would exhibit a significant drop in pH, making it more acidic compared to ethanoic acid.