Classification Soft Moderately Hard Hard Very Hard mg/L or ppm 0-60 61-120 121-180 > 180 PROCEDURE: 1. Dilute the EDTA solution by dispensing 25.0 ml of the given EDTA from a burette into a 250 ml volumetric flask and make up to the mark with distilled water. 2. Rinse and fill the burette with the diluted EDTA solution. 3. Dispense a 20 ml aliquot of the hard water sample into a 250 ml conical flask. Add 2 ml of buffer solution (pH 10). Add 4 drops of the Eriochrome black T indicator solution. 4. Repeat step (3) a further 3 times so that your have four conical flasks of the water solution for the repeat titrations. 5. Titrate the water sample with the EDTA solution until the colour changes from wine-red to pure blue. 6. Repeat the titration until three (3) concordant results are obtained. 7. Express the water hardness in mol L-1 of (Ca²+ + Mg²+). 8. Assuming the water hardness is only due to the presence of Ca²+, express the water hardness in terms of mg L-1 of CaCO3.
Classification Soft Moderately Hard Hard Very Hard mg/L or ppm 0-60 61-120 121-180 > 180 PROCEDURE: 1. Dilute the EDTA solution by dispensing 25.0 ml of the given EDTA from a burette into a 250 ml volumetric flask and make up to the mark with distilled water. 2. Rinse and fill the burette with the diluted EDTA solution. 3. Dispense a 20 ml aliquot of the hard water sample into a 250 ml conical flask. Add 2 ml of buffer solution (pH 10). Add 4 drops of the Eriochrome black T indicator solution. 4. Repeat step (3) a further 3 times so that your have four conical flasks of the water solution for the repeat titrations. 5. Titrate the water sample with the EDTA solution until the colour changes from wine-red to pure blue. 6. Repeat the titration until three (3) concordant results are obtained. 7. Express the water hardness in mol L-1 of (Ca²+ + Mg²+). 8. Assuming the water hardness is only due to the presence of Ca²+, express the water hardness in terms of mg L-1 of CaCO3.
Chapter10: Potentiometry And Redox Titrations
Section: Chapter Questions
Problem 8P
Related questions
Question
100%
please help with 1 and 2, all information given
Calculate the number of moles of Zn2+ in the 20 mL aliquot (show workings)
1.050/65.38= 0.016mol
(0.016x20)/250= 0.00128mol
Calculate the number of moles of EDTA in the average titre (show workings)
Mol EDTA= 0.00122
Volume of EDTA consumed= 0.02106L
0.00122mol/0.02106L=0.0579mol
1. Calculate the concentration of the EDTA solution (show workings)
2. Calculate the concentration of the DILUTED EDTA solution (show workings)
Sample No. |
1 |
2 |
3 |
4 |
Final Burette reading (mL)
|
20.25 |
42.75 |
22.90 |
44.50 |
Initial Burette reading (mL) |
0.05 |
20.25 |
1.50 |
22.90 |
Final-Initial Titre (mL) |
20.20 |
22.50 |
21.40 |
21.60 |
Expert Solution
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
Step by step
Solved in 2 steps with 2 images
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, chemistry and related others by exploring similar questions and additional content below.Recommended textbooks for you