Which one of these has a higher concentration of H⁺ ions? 1 M HCl or 1 M CH₃COOH.

The concentrations of both the acids is same that is 1 molar. Hydrochloric acid is a strong acid with a pH of 1 and hence it dissociates completely in water to give a greater number of hydrogen ions.

On the other hand, acetic acid is a weak acid and it dissociate partially to give lesser hydrogen ions in the solution.

So, 1M HCl will have a higher concentration of hydrogen ions as compared to 1M acetic acid.