On the pH scale, what is the typical average pH range for healthy human skin and hair?

• A. Approximately $9–10$ (basic)
• B. Approximately $7.0$ (neutral)
• C. Approximately $1–2$ (strongly acidic)
• D. Approximately $4.5–5.5$ (slightly acidic)

Answer: (D)

Verified step by step guidance

1. Understand that the pH scale ranges from 0 to 14, where values below 7 are acidic, 7 is neutral, and above 7 are basic (alkaline).
2. Recognize that healthy human skin and hair typically maintain a slightly acidic environment to protect against harmful bacteria and maintain moisture.
3. Recall that the typical pH range for healthy skin and hair is slightly acidic, generally between 4.5 and 5.5.
4. Compare this range to the options given: 9–10 (basic), 7.0 (neutral), 1–2 (strongly acidic), and 4.5–5.5 (slightly acidic).
5. Conclude that the correct typical average pH range for healthy human skin and hair is approximately 4.5–5.5, which is slightly acidic.