Materials required

Analytical balance
Hot plate
pH meter
Burette
Measuring cylinder
Conical flask
Water sample
Ammonia buffer solution
EBT indicator
0.01 M EDTA standard solution

Methods

1. Pipette out 25 ml water in a conical flask.
2. Add 1 ml ammonia buffer solution to adjust pH of around 10 of the sample.
3. Confirm the pH of water sample using pH meter.
4. Add 2-3 drops of EBT indicator in the sample conical flask.
5. Titrate the sample with 0.01M standard EDTA solution until the wine red color changes permanently into blue color
6. Record the volume of EDTA solution used for each titration.
7. Calculate the hardness of sample as per the following equation: