Long Answer: Ascorbic acid (Vitamin C) is a monoprotic weak acid with a pKa of 4.17. When a 25.00mL aliquot of ascorbic
Posted: Thu Jun 09, 2022 7:02 am
Long Answer: Ascorbic acid (Vitamin C) is a
monoprotic weak acid with a pKa of 4.17. When a 25.00mL aliquot of
ascorbic acid was titrated with a 0.1536M NaOH (standardized)
solution, it took 36.85mL of the titrant to reach the endpoint as
identified using phenolphthalein indicator. Use this information
to:
a) Calculate the concentration of ascorbic acid, to the correct
number of significant figures. [2 marks]
b) Determine the initial pH of the solution. Present your
answer to 2 decimal places, and identify any simplifications
made. [3 marks]
c) Determine the pH of the solution at the equivalence point.
Present your answer to 2 decimal places, and identify any
simplifications made. [3 marks]
d) Draw the approximate titration curve for this titration,
using pH (y-axis) and Volume of NaOH
(mL) (x-axis). [1 mark]
e) On the titration curve in c) above, identify the
exact pH and Volume of NaOH Added
at the half equivalence point. [1 mark]
monoprotic weak acid with a pKa of 4.17. When a 25.00mL aliquot of
ascorbic acid was titrated with a 0.1536M NaOH (standardized)
solution, it took 36.85mL of the titrant to reach the endpoint as
identified using phenolphthalein indicator. Use this information
to:
a) Calculate the concentration of ascorbic acid, to the correct
number of significant figures. [2 marks]
b) Determine the initial pH of the solution. Present your
answer to 2 decimal places, and identify any simplifications
made. [3 marks]
c) Determine the pH of the solution at the equivalence point.
Present your answer to 2 decimal places, and identify any
simplifications made. [3 marks]
d) Draw the approximate titration curve for this titration,
using pH (y-axis) and Volume of NaOH
(mL) (x-axis). [1 mark]
e) On the titration curve in c) above, identify the
exact pH and Volume of NaOH Added
at the half equivalence point. [1 mark]