Piperazine, C4H10N2, is a diprotic weak base (pKb1 = 4.22 and pKb2= 8.67). A sample of piperazine is dissolved in 100.0 mL of waterand titrated with 0.500 M HCl. It takes 48.00 mL of HCl to reachthe second equivalence point.
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a) What was the original concentration of the piperazinesolution?
b) Calculate the pH after the following amounts of HCl have beenadded: 0 mL, 12.00mL, 24.00mL,36.00mL, 48.00mL, and 60.00mL
c) Sketch the titration curve for this titration
d) Which of the ollowing indicators could be used to detect thefirst equivalence point? The second?
Indicator Ka ColorChange
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Bromocresolgreen 2.5x10^-5 yellow=> blue-green
PhenolRed 2.5x10^-8 yellow=> red
MethylYellow 3.5x10^-4 red =>yellow
AlizarinYellow 8.9x10^-12 yellow=> red
Piperazine, C4H10N2, is a diprotic weak base (pKb1 = 4.22 and pKb2= 8.67). A sample of piperazine is dissolved in 100.0 mL of waterand titrated with 0.500 M HCl. It takes 48.00 mL of HCl to reachthe second equivalence point.
SHOW ALL WORK
a) What was the original concentration of the piperazinesolution?
b) Calculate the pH after the following amounts of HCl have beenadded: 0 mL, 12.00mL, 24.00mL,36.00mL, 48.00mL, and 60.00mL
c) Sketch the titration curve for this titration
d) Which of the ollowing indicators could be used to detect thefirst equivalence point? The second?
Indicator Ka ColorChange
______________________________________________________________
Bromocresolgreen 2.5x10^-5 yellow=> blue-green
PhenolRed 2.5x10^-8 yellow=> red
MethylYellow 3.5x10^-4 red =>yellow
AlizarinYellow 8.9x10^-12 yellow=> red