student has been trying to determine the concentration of cu2+ in solution by ti
ID: 904439 • Letter: S
Question
student has been trying to determine the concentration of cu2+ in solution by titration with EDTA, using calmagite as an indicator. the student has been having diffeculty because the endpoint in his titration is drawn out over an unacceptably large volume, making endpoint determination very diffecult. his experimintal conditions include 0.00100M EDTA, with the analyte solution buffered at PH=3.0 ( to avoid formation of Cu(OH)2 . based on these conditions, suggest an explaination for his problems and provise guidance in improving his experiment.
Explanation / Answer
Answer:
Cu+2 + EDTA Cu(EDTA)
SInce the buffer used is at pH = 3 is one of the reason difficulty in titration.
Change the analyte solution buffer to a pH more than 7.
The complex formed is also colourless. So the indicator must show change in colour during formation of intermediate Cu -Complex.
The better indicator should be used is Murexide indicator, which gives colour at the end point correctly.
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