Final answer:
A solution with a higher concentration of hydrogen ions than 1.0 × 10-7 M is considered acidic and has a pH less than 7. A concentration less than 1.0 × 10-7 M makes the solution basic with a pH greater than 7. Neutral solutions have a pH of 7, with equal concentrations of hydronium and hydroxide ions.
Step-by-step explanation:
A solution with more hydrogen ions ([H+]) would be considered acidic. When the concentration of hydronium ions ([H3O+]) is greater than 1.0 × 10-7 M, the solution is acidic and will therefore have a pH of less than 7. In contrast, a solution with a hydronium ion concentration less than 1.0 × 10-7 M is basic, and its pH will be greater than 7. For example, a solution with [H3O+] = 4.5 × 10-4 M is highly acidic as 4.5 × 10-4 is much greater than 1 × 10-7. A solution is neutral if the [H3O+] is exactly 1 × 10-7 M, resulting in a pH of 7. Acidic solutions, like vinegar, have a sour taste, while basic solutions, such as baking soda, are bitter and can also cause harm like strong acids.