Soft water is water that contains low levels of dissolved minerals, particularly calcium and magnesium ions, resulting in reduced scaling and improved soap lathering.
Hard water is water that contains high concentrations of dissolved minerals, particularly calcium and magnesium ions. These minerals are acquired as water passes through mineral-rich geological formations. Hard water can cause mineral buildup in pipes, appliances, and surfaces, leading to issues such as scaling and reduced lathering of soaps.
CaCO3 + CO2 + H2O → Ca (HCO3)2
MgCO3 + CO2 + H2O → Mg (HCO3)2
Water hardness refers to the concentration of dissolved minerals, primarily calcium and magnesium ions, in water. The presence of these minerals can affect the performance of water in various applications, such as household use, industrial processes, and even the taste of drinking water. There are two main types of water hardness:
Temporary hardness is caused by the presence of bicarbonate minerals, mainly calcium bicarbonate (Ca(HCO₃)₂) and magnesium bicarbonate (Mg(HCO₃)₂), in water. It is called “temporary” because it can be easily removed or reduced by boiling the water or allowing it to stand exposed to the atmosphere.
Permanent hardness, also known as non-carbonate hardness, is caused by the presence of dissolved sulfates, chlorides, and nitrates of calcium and magnesium in water. Unlike temporary hardness, permanent hardness cannot be removed by boiling.
Boiling water is a simple method to remove temporary hardness. When water is boiled, the heat causes the bicarbonate minerals (calcium bicarbonate and magnesium bicarbonate) to decompose. This decomposition forms insoluble carbonates that precipitate out of the water. Once the water cools, the precipitates can be removed by allowing them to settle or through filtration.
Ca(HCO3)2 → CaCO3 + H2O + CO2
Clark’s method is a chemical approach to remove temporary hardness from water. It involves adding lime (Ca(OH)₂) or slaked lime to the water. The lime reacts with the bicarbonate ions, forming insoluble calcium carbonate (CaCO₃) precipitates. These precipitates can then be removed by settling or filtration, resulting in a reduction in temporary hardness.
Mg(HCO3)2 + Ca(OH)2 → MgCO3 + CaCO3 + 2H2O
Ca(HCO3)2 + Ca(OH)2 → 2CaCO3 + 2H2O
Chemicals are the only way to get rid of permanent hardness. Adding washing soda (Na2CO3) or sodium zeolite removes calcium (Ca2+) and magnesium (Mg2+) as insoluble salts.
Adding washing soda to the calcium and magnesium ions results in the formation of insoluble calcium and magnesium carbonates.
Na2CO3 + CaSO4 → CaCO3 +Na₂SO4
Na2CO3 + MgSO4 → MgCO3 + Na2SO4
Water hardness refers to the concentration of minerals, primarily calcium and magnesium, in water. While water hardness does not pose significant health risks, it can have several disadvantages and negative effects. Here are some disadvantages of water hardness: