Which of the following solutions has the highest concentration of hydrogen ions?

Correct option is C

The correct answer is: (C) pH = 4

The pH scale measures the acidity or alkalinity of a solution. It ranges from 0 to 14, where:

• pH < 7: Acidic (higher concentration of hydrogen ions, H⁺)
• pH = 7: Neutral (equal concentration of hydrogen ions and hydroxide ions)
• pH > 7: Basic or alkaline (lower concentration of hydrogen ions)

The lower the pH, the higher the concentration of hydrogen ions. So, a solution with pH = 4 is more acidic and has a higher concentration of hydrogen ions compared to solutions with pH values of 5, 8, or 10.

• pH 10: Basic solution with fewer hydrogen ions.
• pH 8: Slightly basic with fewer hydrogen ions.
• pH 4: Highly acidic, with the highest concentration of hydrogen ions.

Therefore, pH = 4 has the highest concentration of hydrogen ions.