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Question
Which is the best colored indicator to use in the titration of 0.1 M CH3CO2H(aq) with NaOH(aq)? Why? (Ka of CH3CO2H = 1.8 10-5, Kb of CH3CO2- = 5.6 10-10)
Indicator pKa
Bromcresol Green 4.8
Bromthymol Blue 6.8
Phenolphthalein 9.2
A.Bromcresol Green. The equivalence point for a weak acid titration occurs at low pH.
B.Bromthymol Blue. The pH at the equivalence point is 7.0.
C.Bromcresol Green. The pKa of CH3CO2H and the pKa of the indicator are similar.
D.Phenolphthalein. The pKa of CH3CO2- and the pKb of the indicator are similar.
E.Phenolphthalein. The pH at the equivalence point is near the pKa of the indicator.
Answer
This answer is hidden. It contains 2 characters.
Related questions
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If a chemical reaction is exothermic, but not spontaneous, which of the following must be true?
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