Name two ions which cause temporary hardness of water and two ions which cause permanent hardness.
The presence of calcium and magnesium bicarbonates Ca(HCO3)2 and Mg(HCO3)2 causes temporary hardness in water. The presence of soluble salts of calcium and magnesium, i.e., sulphates and chlorides of calcium and magnesium cause permanent hardness in wate
To determine the ions responsible for temporary and permanent hardness of water, we need to understand the concept first.
Temporary hardness of water is caused by the presence of bicarbonate ions (HCO3-) and carbonate ions (CO32-). These ions can be removed by boiling the water, which causes them to decompose and form insoluble carbonate precipitates.
On the other hand, permanent hardness of water is caused by the presence of dissolved calcium ions (Ca2+) and magnesium ions (Mg2+) in the form of sulfates, chlorides, or nitrates. Unlike bicarbonate and carbonate ions, these ions cannot be removed by boiling since they do not decompose.
So, in summary:
Ions causing temporary hardness:
- Bicarbonate ions (HCO3-)
- Carbonate ions (CO32-)
Ions causing permanent hardness:
- Calcium ions (Ca2+)
- Magnesium ions (Mg2+)
To identify other ions causing water hardness, you can test the water using inexpensive home water testing kits or send a water sample to a laboratory for complete analysis.