5 Questions
What are the two types of hardness of water, and how do they differ from each other?
The two types of hardness of water are temporary hardness and permanent hardness. Temporary hardness is due to bicarbonates of calcium and magnesium, which can be removed by boiling the water. On boiling, the bicarbonates are converted into insoluble carbonates of calcium and magnesium. Permanent hardness is due to the presence of other soluble salts of calcium, magnesium, and other metals, which can be removed only by chemical treatments.
What is the difference between temporary hardness and permanent hardness?
Temporary hardness is due to bicarbonates of calcium and magnesium, which can be removed by boiling the water. On boiling, the bicarbonates are converted into insoluble carbonates of calcium and magnesium. Permanent hardness is due to the presence of other soluble salts of calcium, magnesium, and other metals, which can be removed only by chemical treatments.
How is the hardness of water determined?
The hardness of water is determined by titrating a known volume of water sample with EDTA, using Eriochrome Black T (EBT) as an indicator, in the presence of ammonium hydroxide ammonium chloride buffer (pH 10).
What is total hardness, and how is it expressed?
The sum of temporary hardness and permanent hardness is known as total hardness. The hardness is expressed in ppm or mg/L of calcium carbonate equivalent.
What causes hard water to not give lather easily with soap?
Hard water does not give lather easily with soap because the hardness causing ions react with soap to form insoluble soap, precipitating in the form of a scum.
Test your knowledge of water hardness with this quiz! Learn about the presence of dissolved salts like calcium and magnesium, and their impact on soap lathering. Explore the concepts of temporary hardness and the removal of bicarbonates through boiling.
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