Final answer:
A high concentration of hydrogen ions indicates a very acidic solution.
Step-by-step explanation:
A high concentration of hydrogen ions in a solution indicates that the solution is very acidic. The concentration of hydrogen ions is measured on the pH scale, with lower pH values indicating higher acidity. For example, a solution with a pH of 1 is more acidic than a solution with a pH of 6. On the other hand, a solution with a high concentration of hydroxide ions would be considered basic or alkaline.
Learn more about acidity levels in solutions