Final answer:
An acidic solution has a pH less than 7, characterized by a higher concentration of hydronium ions and a lower concentration of hydroxide ions.
Step-by-step explanation:
The true statement about an acidic solution is that it has a pH lower than 7. Acids are characterized by a higher concentration of hydronium ions (H₃O⁺) compared to pure water and, consequently, a low pH value.
An acidic solution has a higher hydronium ion concentration than the hydronium ion concentration of pure water, which is 1.0 × 10⁻⁷ M at 25 °C. Hence, acidic solutions have a corresponding lower concentration of hydroxide ions (OH⁻) in contrast to bases, which exhibit the opposite behavior with higher hydroxide ion concentrations.