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QJEEM23Chbe1d: JEE Main 2023 Chemistry - Class 11 JEEM23Chbe1d Solution: The incorrect statement for the use of indicators in acid-base…
The incorrect statement for the use of indicators in acid-base titration is :
Multiple Choice Options
- A Phenolphthalein is a suitable indicator for a weak acid vs strong base titration.
- B Methyl orange may be used for a weak acid vs weak base titration.
- C Methyl orange is a suitable indicator for a strong acid vs weak base titration.
- D Phenolphthalein may be used for a strong acid vs strong base titration.
Step-by-Step Verified Solution
| Indicator | pH range |
|---|---|
| Methyl orange | 3.2 - 4.5 |
| Phenolpthalein | 8.3 - 10.5 |
Option B is the incorrect statement for the use of indicators in acid-base titration.
Methyl orange is a suitable indicator for a strong acid vs strong base titration, not for a weak acid vs weak base titration. In a weak acid vs weak base titration, the pH at the equivalence point is typically around 7, which is within the pH range where methyl orange undergoes a color change. Therefore, methyl orange is not suitable for use in weak acid vs weak base titrations.
The other options are correct:
Phenolphthalein is a suitable indicator for a weak acid vs strong base titration because the pH at the equivalence point is basic, which causes phenolphthalein to undergo a color change.
Methyl orange is a suitable indicator for a strong acid vs weak base titration because the pH at the equivalence point is acidic, which causes methyl orange to undergo a color change.
Phenolphthalein may be used for a strong acid vs strong base titration because the pH at the equivalence point is basic, which causes phenolphthalein to undergo a color change.