The water which gives low or no froth with soap and detergent is known as hard water. Hard water is due to the presence of bicarbonates,
Hard water is of two types
Temporary hardness: Temporary hardness of water is due to the presence of bicarbonate of calcium and magnesium in the water. It can be easily removed by simply boiling water. Calcium bicarbonate and magnesium bicarbonates are converted into carbonate forms
Ca(HCO3)2 ———> CaCO3 ↓ + H2O + CO2
Mg(HCO3)2 ————> MgCO3 + H2O + CO2
Permanent hardness: P
Determination of total hardness
Both temporary and permanent hardness of water is determined by complexometric titration using EDTA (ethylene diamine tetraacetate) as a complexing agent in the presence of t
For total hardness: For determination of total hardness of water, a sample of 50 ml cold water is titrated with EDTA by using solo chrome black T prepared in the basic buffer solution till wine red color changes into clear blue color.
|S.N||Vol. of water||Vol. of EDTA(Burrette reading||Concurrent reading|
Effect of hard water
- Soap and detergents do not give froth properly.
- It corrodes water pipe, metallic pots
- It fads the color of clothes, mats, etc.
- Also, it affects and can damage the human body parts such as the kidney, liver.
Also Read: Chemical Oxygen Demand (COD) AND Dissolved Oxygen (DO)