In aqueous solution, the pH of a substance is a measure of its:

Alkaline (basic) solutions have a pH in which of the following ranges at $25°C$?

On the pH scale, distilled water with $\mathrm{pH}=7$ at $25°C$ is considered:

Ammonium thioglycolate (often used in hair relaxers) is basic. Which pH range best matches ammonium thioglycolate relaxers?

On the pH scale, which pH range corresponds to acidic solutions?

On the pH scale for aqueous solutions, what is the smallest possible pH value (theoretical, not limited by practical measurement)?

Distilled water at $pH=7$ (at $25°C$) is considered which of the following?

Hair, skin, and nails are generally considered to be slightly acidic. Which pH range best describes their typical surface pH?

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