Answer:
pH = 9: Basic; pH = 2.3: acidic; pH = 11: basic; pH = 5: Acidic; [H⁺] = 0.0056M: Acidic; [H⁺] = 3.45E-9M: Basic
Step-by-step explanation:
A solution is defined as acidic when pH < 7 and as basic when pH > 7.
Also, pH = -log[H⁺].
Thus:
pH = 9: >7 → Basic
pH = 2.3: <7 → Acidic
pH = 11: >7 → Basic
pH = 5: <7 → Acidic
[H⁺] = 0.0056M, pH = -log0.0056M = 2.25: <7: Acidic
[H⁺] = 3.45E-9M, pH = 8.46: > 7: Basic