College of Massage Therapists of British Columbia (CMTBC) Practice Exam

What is true about pH in relation to the concentration of hydrogen ions?

1. A higher concentration of H ions results in a basic solution

2. A higher concentration of H ions results in an acidic solution

3. The pH level has no correlation with H ion concentration

4. A lower concentration of H ions indicates acidity

The correct answer is: A higher concentration of H ions results in an acidic solution

The statement that a higher concentration of hydrogen ions results in an acidic solution is accurate due to the fundamental relationship defined by the pH scale. The pH scale ranges from 0 to 14, with lower values indicating higher acidity. This is because pH is a logarithmic scale that represents the concentration of hydrogen ions (H⁺) in a solution. Specifically, as the concentration of hydrogen ions increases, the pH value decreases, confirming that the solution becomes more acidic. In detail, a solution with a high hydrogen ion concentration, such as lemon juice or vinegar, has a low pH, typically below 7, which classifies it as acidic. Conversely, solutions with low hydrogen ion concentrations, such as baking soda or soap, have higher pH values above 7, indicating they are basic or alkaline. The other options do not hold up under scrutiny; for example, a higher concentration of H ions cannot result in a basic solution and would not be accurate. Additionally, the claim that pH has no correlation with H⁺ ion concentration is misleading because the very definition of pH is based on that correlation. Lastly, a lower concentration of H ions does not indicate acidity; rather, it suggests a move towards neutrality or