Aim : To determine the Total Hardness, Alkalinity, Chlorides, TDS in water.
1. Test for Total Hardness ( Hardness due to presence of calcium and magnesium )
Procedure -
Take 50 ml of water in a conical flask.
Add one total hardness indicator tablet ( Erichrome Black T indicator ) and mix well.
Add 5 drops of ammonia buffer solution and shake well.
Titrate the mixture against 0.02N EDTA ( Ethylene Diamine Tetra acetic Acid) solution.
When the colour is changed from violet to blue, stop titration and and take burette reading.
Calculation -
Total Hardness ( mg/l ) = ( Burette reading*1000 )/ sample taken
2. Test for Alkalinity
Procedure -
Take 50 ml of sample in a clonical flask.
Add 3-4 drops of methyl orange indicator and mix well
Titrate it against 0.1 N Hcl.
When colour changes from yellow to orange, stop titration and note burette reading.
Calculation -
Alkalinity (mg/l) = (Titre value*N of HCl*50*1000)/ml of sample taken
3. Test for Chlorides
Procedure -
Take 50 ml of sample in a conical flask.
Add 1 ml Potassium Chromate indicator and mix well.
Titrate against AgNO3 solution.
When a pinkish yellow colour is reached, stop titration and note the reading.
Calculation -
Chlorides (mg/l) = ( Titre value*Normality of AgNO3*35.46*1000 )/ ml of sample taken.
4. Test for Total Dissolved Solids (TDS)
TDS can be checked through TDS meter and can also be checked manually.
Procedure -
Take 100 ml of water in a pre weighed beaker.
Boil the water to evaporate all the water.
Remove the beaker from fire when a little water is left in the beaker.
Keep the beaker in Hot Air Oven to evaporate rest of the water.
Take out the beaker and allow to cool.
Weigh the beaker.
Calculation -
TDS in ppm = [(W2 - W1)/ml of sample taken]*10^6
Where W1 = weight of the dry empty beaker
W2 = weight of beaker with evaporated water
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| Author: ankita | Member Level: Bronze | Revenue Score:  |
great work was a great help in my project for some calculations...thanks a lot
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