Phenolphthalein acidity is prevalent above which pH value?

Phenolphthalein acidity is prevalent above which pH value?

• A. 3.9
• B. 4.0
• C. 4.1
• D. 4.3

Answer: (D)

Phenolphthalein acidity shows up in the pH range where the phenolphthalein response becomes relevant in standard titration tests. The threshold value used in practice is about 4.3. Once the solution’s pH is above roughly 4.3, the portion of acidity that is described as phenolphthalein acidity becomes detectable and significant in calculations. That’s why the correct choice is 4.3. Values below that remain in a pH region where this form of acidity isn’t the dominant factor, so they aren’t used to describe phenolphthalein acidity.

Phenolphthalein acidity shows up in the pH range where the phenolphthalein response becomes relevant in standard titration tests. The threshold value used in practice is about 4.3. Once the solution’s pH is above roughly 4.3, the portion of acidity that is described as phenolphthalein acidity becomes detectable and significant in calculations. That’s why the correct choice is 4.3. Values below that remain in a pH region where this form of acidity isn’t the dominant factor, so they aren’t used to describe phenolphthalein acidity.