On the pH scale, which statement correctly describes acids and bases?

• A. Acids have pH below 7
• B. Bases have pH above 7
• C. pH of 7 neutral
• D. All of the above

Answer: (D)

Understanding the pH scale: it shows how acidic or basic a solution is. Acids have a pH below 7, bases have a pH above 7, and pH 7 is neutral. Since each statement is true, all of them together describe the concept correctly. For context, lemon juice has a pH well below 7, household ammonia sits well above 7, and pure water at room temperature is around 7. This matters in hazmat work because pH helps assess corrosivity and guides how to neutralize or contain spills safely.