A pH of 8 is ___ times more alkaline than a pH of 7.

• A. 5
• B. 10
• C. 25
• D. 50

Answer: (B)

A pH scale measures how acidic or alkaline a substance is, ranging typically from 0 to 14. Each whole number change on the pH scale represents a tenfold change in acidity or alkalinity. Therefore, a pH of 7 is considered neutral, while values above 7 indicate alkalinity.

When comparing a pH of 8 to a pH of 7, the difference is one whole number. Since each pH unit represents a tenfold increase, a pH of 8 is ten times more alkaline than a pH of 7. This foundational concept of the pH scale reflects the logarithmic nature of pH measurement, where a change of 1 in pH signifies a tenfold difference in hydrogen ion concentration.

Understanding this principle is vital for estheticians, as it impacts the products they use and recommend, particularly when considering skin types and conditions that may be affected by pH levels.