Calcium Concentration in Milk: EDTA Titration Problem and Buffering Explained"

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    Edta Titration
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SUMMARY

The discussion focuses on calculating the concentration of calcium in powdered milk using EDTA titration. A sample weighing 1.450 g was mixed with a pH 11.5 buffer and required 31.62 mL of 1.539x10^-2 M EDTA for the endpoint. The reaction involves a 1:1 complexation between EDTA and calcium, with Calagmite indicator signaling the endpoint by changing color. The necessity of buffering is emphasized to maintain pH stability during the titration process.

PREREQUISITES
  • Understanding of EDTA titration methodology
  • Knowledge of buffer solutions and their role in pH stabilization
  • Familiarity with the Calagmite indicator and its color change properties
  • Proficiency in using the M1V1 = M2V2 equation for titration calculations
NEXT STEPS
  • Research the principles of EDTA titration and its applications in calcium analysis
  • Study the preparation and use of buffer solutions, particularly at pH 11.5
  • Explore the properties and mechanisms of colorimetric indicators like Calagmite
  • Learn advanced titration techniques and calculations for complexometric titrations
USEFUL FOR

Chemistry students, laboratory technicians, and professionals involved in food science or quality control who are interested in calcium quantification in dairy products.

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Homework Statement



A sample of powdered milk weighing 1.450 g was mixed with an aqueous buffer of pH 11.5. A few drops of Calagmite indicator were added and the solution required 31.62 mL of 1.539x10^-2 M EDTA to reach the end-point color change.

a. Calculate the concentration of calcium in the milk.
b. Why does the solution need to be buffered?

Homework Equations



M1V1 = M2V2

The Attempt at a Solution


I really don't know how to solve this problem
 
Physics news on Phys.org
EDTA complexes 1:1 with calcium. Calagmite turns red when it is added to the milk by complexing with free calcium until enough EDTA is added to grab it away. When enough EDTA has been added, the calcium-free indicator fades to colorless.
 

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