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InterviewSolution
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Explain the action of phenolphthalein indicator in the titration of acetic acid, sodium hydroxide |
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Answer» Solution :Acetic ACID is a WEAK acid having a pH value of more than 6. Sodium hydroxide is a strong base and additionsof `OH^(-)` ions neutralises the `H^(+)` ions formed by the dissociation of acetic acid. Since `H^(+)` ion concentration is very low, the addition of further `OH^(-)` ions increases the pH value ABRUPTLY. Therefore, the titration range of this reaction lies between 6.5 and 10.0. The pH range of phenolphthalein is between 8.2 and 10.0 hence, it undergoes colour change in this range. Hence, it ACTS as a suitable indicator for this titration |
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