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If very small amount of phenolphthalein ...

If very small amount of phenolphthalein is addded to 0.15 M solution of sodium benzoate , what fraction of the indicator will exist in the coloured form ?
`K_(a("Benzoic acid")) = 6.2 xx10^(-5)`
`K_(w(H_(2)O))= 1xx10^(-14)`
`K_(In("phenolphthalein"))=3.16 xx10^(-10)` .

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AI Generated Solution

To solve the problem of determining the fraction of phenolphthalein that exists in the colored form when a small amount is added to a 0.15 M solution of sodium benzoate, we will follow these steps: ### Step 1: Understand the System Phenolphthalein is an acid-base indicator that changes color based on the pH of the solution. In this case, we need to find out how much of the phenolphthalein exists in its deprotonated (colored) form in a solution of sodium benzoate, which is a salt of a weak acid (benzoic acid). ### Step 2: Calculate the pH of the Sodium Benzoate Solution Sodium benzoate (C6H5COONa) will hydrolyze in water to produce benzoic acid (C6H5COOH) and hydroxide ions (OH⁻). The equilibrium can be represented as follows: ...
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