At a pH less than 8.3, phenolphthalein appears as what color?

At a pH less than 8.3, phenolphthalein appears as what color?

• A. Pink
• B. Clear
• C. Yellow
• D. Red

Answer: (B)

Phenolphthalein is a pH indicator commonly used in titrations and other chemical analyses. Its primary function is to visually indicate changes in pH. In acidic solutions (pH less than approximately 8.3), phenolphthalein is colorless, which aligns with the provided answer of clear. As the pH of a solution increases and approaches a neutral state (around pH 7 to 8.3), phenolphthalein changes from clear to pink as it transitions into a more basic environment. At a pH above 8.3, phenolphthalein is distinctly pink. Therefore, when the solution is below a pH of 8.3, it does not exhibit any color and remains clear, which is why this answer is accurate. Understanding this transition is crucial for interpreting results in laboratory settings, particularly in water quality analysis, where accurate pH measurement is essential.

Phenolphthalein is a pH indicator commonly used in titrations and other chemical analyses. Its primary function is to visually indicate changes in pH. In acidic solutions (pH less than approximately 8.3), phenolphthalein is colorless, which aligns with the provided answer of clear.

As the pH of a solution increases and approaches a neutral state (around pH 7 to 8.3), phenolphthalein changes from clear to pink as it transitions into a more basic environment. At a pH above 8.3, phenolphthalein is distinctly pink. Therefore, when the solution is below a pH of 8.3, it does not exhibit any color and remains clear, which is why this answer is accurate. Understanding this transition is crucial for interpreting results in laboratory settings, particularly in water quality analysis, where accurate pH measurement is essential.