The pH of a solution depends on its _________ concentration.

Correct option is A

The correct answer is (a) Hydronium ions.
· The pH of a solution depends on its hydronium ion (H₃O⁺) concentration. pH is a measure of the acidity or basicity of a solution, and it is calculated as the negative logarithm of the hydronium ion concentration.
pH=−log[H₃O⁺]
Information Booster:
· Oxide ions and hydride ions do not directly influence pH.
· Hydroxyl ions (OH⁻) affect pH in the context of basicity, but pH is specifically calculated based on the concentration of hydronium ions.