Final answer:
The pH of hair is typically between 4.5 and 5.5, which falls within the acidic range of the pH scale.
Step-by-step explanation:
The pH scale ranges from 0 to 14, where anything below 7 is acidic and above 7 is alkaline. The pH of hair is typically between 4.5 and 5.5, which falls within the acidic range. This slightly acidic pH helps to protect the hair and maintain its health.