HAZMAT Technician Practice Exam

What is the pH value range of a caustic (base)?

1. 0 to 7

2. 7 to 14

3. 5 to 9

4. 3 to 7

The correct answer is: 7 to 14

A caustic substance, commonly known as a base, has a pH value that ranges from 7 to 14. In this scale, a pH of 7 is considered neutral, while values above 7 indicate increasing alkalinity, representing the strength of the base. The higher the pH value, the more caustic the substance is. In practical terms, bases can react with acids in a neutralization reaction, producing water and salt, which is fundamental in various chemical processes. Understanding this property is crucial for handling caustic materials safely, as they can cause burns or corrosion when in contact with biological tissues. The other ranges listed do not depict caustic substances: a pH value from 0 to 7 indicates acidity, while values from 5 to 9 fall within the range of slightly acidic to neutral, not reaching the level characteristic of bases. The range of 3 to 7 also suggests a transition from acidic to neutral conditions, which again does not include the highly alkaline nature of caustic materials. This emphasizes the importance of recognizing the properties of substances based on their pH levels in hazardous material situations.