acid-base titration

Question

Phenolphthalein is suitable indicator for titration of:

RankGuru · Accepted Answer

An indicator is suitable if its **color change interval** includes the **pH at the equivalence point**.
- For a **Weak Acid vs Strong Base** titration (e.g., Acetic acid vs $NaOH$), the salt formed (Sodium acetate) undergoes basic hydrolysis. The pH at the equivalence point is $> 7$ (typically $8$ to $9$).
- **Phenolphthalein** changes color in the range **$pH \, 8.3 - 10.0$** (Colorless to Pink).
- Thus, it fits perfectly for this titration. It is **NOT** suitable for Strong Acid vs Weak Base because the end point pH would be $< 7$.

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acid-base titration

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