The solution with the lowest pH is the most acidic solution.
Explanation:
- The pH scale ranges from 0 to 14
- pH < 7 → acidic
- pH = 7 → neutral
- pH > 7 → basic
- Lower pH means higher concentration of H⁺ ions
Examples:
- Hydrochloric acid (HCl) → very low pH (around 1–2)
- Sulfuric acid (H₂SO₄) → very strong acid
- Nitric acid (HNO₃) → low pH
Among common solutions, strong acids have the lowest pH.
Key Insight:
- The strength and concentration of the acid determine how low the pH is
- More H⁺ ions → lower pH
Conclusion:
The solution with the lowest pH is a strong acid, as it has the highest concentration of hydrogen ions.