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The difference between hard water and soft water helps determine the type of minerals found in this water. Hard and soft water are two types of water that may be present in one's home.
- Difference between hard water and soft water help determine which water is prefered for drinking.
- Water is graded on a scale ranging from hard to soft based on its mineral composition.
- It includes minerals and compounds, even though it appears to be clear.
- The concentration of particular minerals, such as the salts of calcium and magnesium determines the hardness of water.
- Soft water contains only sodium cations that have a salty texture.
- Rainwater is a type of soft water, and water inside wells is a type of hard water.
Key Terms: Difference between hard water and soft water, Hard Water, Soft Water, Calcium, Magnesium, Minerals, Water, Calcium Carbonate, Gypsum, Cation
Hard Water
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Hard water is a type of water that has a high abundance of calcium and magnesium, which are two naturally occurring minerals in water. The higher the concentration of these minerals in the water, the higher it will rank on the hardness scale.
- Calcium and magnesium are important for everyday health, although they are not required for water consumption.
- Hardness in water can harm your property.
- Water with calcium carbonate concentrations of 60-120 mg/l is moderately hard.
- According to the WHO, those with a range of 120-180 mg/l is hard, and more than 180 mg/l is very hard.
- The capacity of water to react with soap and generate lather is measured by its hardness.
- Instead of lather, hard water produces an intractable curd when soap is used.
- After washing, hard water can leave a residue on your hands, skin, and hair.
- Your hair and skin may become more dry and fragile as a result.
- You may notice consequences on your hygiene if your water is high on the water hardness scale.
Example of Hard WaterExample: You may see spots or a film of residue on your dishes, shower, or clothing after using water for cleaning. Furthermore, particles may be found inside household equipment, such as the dishwasher or the washing machine.
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Hard water and Soft water
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Causes of Hardness of Water
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The concentration of multivalent cations in a given water sample is commonly used to determine the hardness of the water. Multivalent cations are metal complexes with positive charges that are always greater than 1+.
- The cations have a positive charge of 2+ in most cases.
- Certain cations are very common in hard water such as Ca2+ and Mg2+.
- Through mineral leaching, such ions can reach a reservoir of water within an aquifer.
- Gypsum and calcite are two common calcium-containing minerals.
- Dolomite (another calcium-containing mineral) is a common magnesium mineral.
- There are just a few ions dissolved in rainwater and filtered water, they are considered soft water samples.
Types of Hard Water
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The different types of hard water are as follows:
Temporary Hardness of Water
The presence of dissolved bicarbonate minerals in the water, such as calcium bicarbonate and magnesium bicarbonate, causes temporary hardness. Water becomes hard due to the presence of metal cations.
- This "temporary" hardness is generated by sulphate and chloride compounds.
- It can be decreased by boiling the water.
- Boiling leads to the synthesis of carbonate from the bicarbonate.
- It causes calcium carbonate to precipitate out of the solution, which causes water to become softer when cooled.
- The reaction that occurs when temporary hardness is removed from water by boiling can be represented as follows:
Ca2+ + 2HCO3- Heat → CaCO3(S) + H2O + CO2
Permanent Hardness of Water
Hardness (mineral content) that cannot be eliminated by boiling is known as permanent hardness. The presence of calcium sulphate and/or magnesium sulphates in the water is the reason for this.
- It do not precipitate out when the temperature rises
- Water hardness is frequently represented in units other than molar concentration.
- It includes german degrees (°dH): 10 mg/L CaO is equal to 1°dH.
Soft Water
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Soft water, unlike hard water, is free of abrasive minerals that can harm your property and body. To put it another way, it is kinder to both your body and your home.
- It lacks calcium and magnesium and can help avoid scale accumulation in your home's appliances and pipes.
- Most importantly, it improves soap's effectiveness as compared to hard water, which can deactivate the soap's components.
- Soft water can battle the dryness and stickiness induced by cold weather, low humidity, and hard water in terms of health.
- After each wash, your hair and skin will be softer and silkier.
- Water softening systems like Culligan's Water Softeners can help soften water so you can clean your home more efficiently.
Hard water and Soft water
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Difference between Hard Water and Soft Water
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The difference between hard water and soft water are as follows:
| Hard Water | Soft Water |
|---|---|
| Mineral concentration is greater than normal water. | Mineral concentration is less. |
| It has a calcium carbonate content of greater than 60 mg per liter. | It has a calcium carbonate content of lesser than 60 mg per liter. |
| It mainly contains calcium and magnesium ions. | It contains calcium, magnesium, and sodium ions. |
| Instead of lather, it produces an insoluble curd with soap. | It forms lather with soap. |
| Can not be used for drinking purpose. | Can be used for drinking purpose. |
| It has a characteristic taste. | Salty taste. |
| Water runs through limestone, chalk, and other rocks to form. | Rainwater is usually a soft liquid. Aside from that, hard water can be softened by running it through an ion exchange resin. |
| It is not suitable for boilers and other machines. | It can be used in boilers and other machines. |
| It has a negative impact on the skin and hair. | No side effects on skin and hair. |
| It forms hard calcium or magnesium salt deposits on taps, showerheads, and other fittings. | It does not form hard calcium or magnesium salt deposits on taps, showerheads, and other fittings. |
Things to Remember
- The difference between hard water and soft water determines the calcium carbonate content.
- Water with calcium carbonate concentrations of 60-120 mg/l is moderately hard.
- Calcium and magnesium make up more than 80% of a person's entire daily consumption on average.
- Drinking water contains 5-20% calcium and magnesium.
- Calcium (30%) and magnesium (35%) gets absorbed.
- While boiling hard water, the soluble salts of Mg(HCO3)2 is converted to insoluble carbonates MgCO3.
Sample Questions
Ques. How is the hardness of water treated? (3 marks)
Ans. Hard minerals are physically removed from the water during mechanical treatments. An ion exchange water softener is the most prevalent mechanical method for softening water. The hardness minerals in the water are replaced with another substance via an ion exchange procedure.
- The hardness of water can also be removed by washing soda.
- Insoluble sulphide and chlorides will react with washing soda.
- This will convert hard water is converted to salt water.
Ques. Explain: (A) Can drinking hard water cause problems (B) What are the disadvantages of soft water? (2 marks)
Ans. (A) Drinking hard water does not cause any major health risks. Hard water, on the other hand, can cause dry skin and hair. Washing your hair with harsh water on a regular basis can irritate your scalp.
(B) Drinking soft water on a regular basis raises sodium levels, which can cause a variety of health concerns, including high blood pressure. It becomes more volatile when softened, allowing it to pick up more contaminants from your pipes.
Ques. Is it safe to drink hard water? (1 mark)
Ans. Hard water is not harmful to your health. Indeed, multiple studies have found that hard drinking water contributes only a modest amount of calcium and magnesium to overall human dietary needs. Many scholars looked into the relationship between water hardness and cardiovascular disease mortality.
Ques. Why is water containing large amounts of dissolved calcium and magnesium salts referred to as “hard water”? (2 marks)
Ans. Hard water (also known as water hardness) is a frequent property associated with water that contains dissolved magnesium and calcium chemical compounds, as well as other trivalent and divalent metallic elements. Due to the soap-wasting characteristic of hard water, the term "hardness" was first given to water that was difficult to wash in.
Ques. What are the disadvantages associated with hard water? (2 marks)
Ans. The most significant disadvantage of hard water is that it wastes soap. Hard water does not readily lather with a soap solution during bathing activities, resulting in gritty scum on the bath and body. Due to the presence of dissolved salts that provide the characteristic of hardness to water, the boiling point of water rises during cooking activities. This may have a negative impact on the food's flavor.
Ques. Why is hard water undesirable? (2 marks)
Ans. The term "hard water" refers to water that has a high concentration of dissolved calcium and magnesium. Hard water isn't harmful to your health, but it can be a pain to deal with because of mineral buildup on plumbing fixtures and poor soap and/or detergent results. Water is a powerful solvent that absorbs pollutants quickly.
Ques. Explain: (A) How to check hard water and soft water (B) Does Brita remove hardness? (2 marks)
Ans: (A) Lather formation is the simplest and most effective approach to determine the hardness of the water. Soft water is water that readily produces lather with soaps and detergents, whereas hard water is water that does not readily create lather with soaps and detergents.
(B) Despite the fact that Brita uses an ion exchange filter, its filters are capable of removing elements like cadmium and copper. Calcium and magnesium do not have the same mechanism. As a result, using a Brita filter to soften hard water will not work.
Ques. Do water softeners make your water salty? (1 mark)
Ans. It's a popular misperception that water softening increases the salt content of your water. Despite the fact that physical salt is fed into the water softener, the salt never enters the water supply.
Ques. What is the difference between hard water and soft water? (5 marks)
Ans. The difference between hard water and soft water are as follows:
| Hard Water | Soft Water |
|---|---|
| Mineral concentration is greater than normal water. | Mineral concentration is less. |
| It has a calcium carbonate content of greater than 60 mg per liter. | It has a calcium carbonate content of lesser than 60 mg per liter. |
| It mainly contains calcium and magnesium ions. | It contains calcium, magnesium, and sodium ions. |
| Instead of lather, it produces an insoluble curd with soap. | It forms lather with soap. |
| Can not be used for drinking purpose. | Can be used for drinking purpose. |
| It has a characteristic taste. | Salty taste. |
Ques. Deterine the cause of hardness of water? (4 marks)
Ans. The concentration of multivalent cations in a given water sample is commonly used to determine the hardness of the water. Multivalent cations are metal complexes with positive charges that are always greater than 1+.
- The cations have a positive charge of 2+ in most cases.
- Certain cations are very common in hard water such as Ca2+ and Mg2+.
- Through mineral leaching, such ions can reach a reservoir of water within an aquifer.
- Gypsum and calcite are two common calcium-containing minerals.
- Dolomite (another calcium-containing mineral) is a common magnesium mineral.
- There are just a few ions dissolved in rainwater and filtered water, they are considered soft water samples.
Ques. Explain the temporary hardness of water? (3 marks)
Ans. The presence of dissolved bicarbonate minerals in the water, such as calcium bicarbonate and magnesium bicarbonate, causes temporary hardness. Water becomes hard due to the presence of metal cations.
- This "temporary" hardness is generated by sulphate and chloride compounds.
- It causes calcium carbonate to precipitate out of the solution, which causes water to become softer when cooled.
- The reaction that occurs when temporary hardness is removed from water by boiling can be represented as follows:
Ca2+ + 2HCO3- Heat → CaCO3(S) + H2O + CO2
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