How to distinguish between hard water and soft water What to use to distinguish between hard water a

1.Hard water Natural water containing calcium salts and magnesium salts. In general, groundwater such as well water and spring water has a large salt content, and surface water such as river water and lake water has a small salt content.

In hard water, calcium, magnesium can be present in the form of carbonates, bicarbonates, sulfates, chlorides, and nitrates. When calcium and magnesium in hard water mainly exist in the form of bicarbonate, such as Ca(HCO3)2, Mg(HCO3)2, it is called temporary hard water, when this hard water is heated and boiled, bicarbonate will decompose into carbonate and precipitate to remove If calcium and magnesium in hard water mainly exist in the form of sulfate, nitrate and chloride, it is called permanent hard water, and they cannot be removed by boiling. The calcium and magnesium salts in hard water can interact with soap (sodium stearate) to form insoluble stearate, reducing the decontamination ability of soap.

If hard water is used in the boiler, calcium and magnesium salts will form scale on the inner wall of the boiler when heated. Reducing the thermal conductivity of the boiler, increasing energy consumption, and even shortening the life of the boiler, sometimes clogging the pipes. Therefore, boiler water must be softened (see).

The salt content in hard water is usually expressed in terms of hardness. The hardness unit is often expressed as "degree", 1 degree is equivalent to 10mg of CAO per liter of water, and the total hardness of drinking water is required to be less than 25 degrees. 2.

Soft water Natural water with only a small amount of soluble calcium and magnesium salts, or hard water that has been softened. Natural soft water generally refers to river water, river water, and lake (freshwater lake) water. Softened hard water refers to demineralized water obtained when the calcium and magnesium salt content is reduced to milligrams.

Although boiling can turn temporarily hard water into soft water, it is extremely uneconomical to use this method in industry to treat large amounts of water. The methods of softening water are: lime-soda method.

First, the hardness of the water is measured, and then a certain amount of calcium hydroxide and sodium carbonate are added, and the calcium and magnesium ions in the hard water are precipitated and precipitated: Ca(HCO3)2 Ca(OH)22CaCO3 2H2O mg(HCO3)2 2Ca(OH)2 2CaCO3 2H2O CaSO4 Na2CO3CaCO3 Na2SO4 Phosphate soft water method. For boiler water, sodium phosphite (Napo3) can be added as a water softener, which forms a complex with calcium and magnesium ions, and calcium and magnesium will not precipitate in the form of precipitation when the water is boiled, so that scale will not be formed.

This method is not suitable for the softening of drinking water. Ion exchange method. Although zeolite and ion exchanger are insoluble in water, the sodium ions and hydrogen ions in them can exchange with calcium and magnesium ions in hard water, so that calcium and magnesium ions are adsorbed by zeolite, artificial zeolite and ion exchangers and removed.

Wow, why is it so complicated! Use soapy water to distinguish between them. There are more bubbles in hard water and less in soft water

Hello dear, glad to answer for you, <>

Method 1: The main way to distinguish between hard water and soft water is to use soapy water to identify, soft water with more foam, and hard water with less foam Therefore, the answer is: take two test tubes and add a little hard water and soft water respectively, and then add 2-3 drops of soapy water to the test tube respectively to shake, the foam is more soft water, and the foam is less hard water Method 2:

It can also be distinguished by the method of heating, after heating, it is soft water that does not generate scale or is not easy to generate scale, and it is hard water that is easy to generate scale, so the answer is: take two test tubes and add a little hard water and soft water respectively, and then heat the one that does not generate scale or is not easy to generate scale for soft water, and the one that is easy to generate scale is hard water

Soft and hard water can be distinguished by soapy water.

Soft water refers to water that does not contain or contains less soluble calcium and magnesium compounds; Hard water refers to water that contains more soluble calcium and magnesium compounds.

In the laboratory and life, we can use soapy water to identify hard water and soft water, take a small amount of water sample in a beaker, add an appropriate amount of soapy water, stir, if there is more foam and less scum, it is soft water; If there is less foam and more scuss, it is hard water. You can also take a certain amount of water sample in the evaporation dish, evaporate dry, and skillfully close if there are many white solid residues for hard water, otherwise for soft water. Because hard water contains more inorganic salt ions, it has strong conductivity, and conductivity can also be used to distinguish soft and hard water.

There are many ways to soften hard water, and boiling is usually used to reduce the hardness of water, but it cannot convert all soluble calcium and magnesium compounds into precipitate. Therefore, distillation is often used to obtain water with a high degree of purification. In addition, ion exchange methods, precipitation methods, electrodialysis methods, and electrodialysis methods are also used to soften hard water.

The impact of soft water in our lives:

Soft water tastes excellent when drunk, making it the best choice for everyday drinks. Cooking rice and cooking vegetables in soft water makes the rice grains fluffier and the dishes more delicious.

Cleanse with soft water** to thoroughly remove dirt and residual makeup from pores. After bathing**, it is not tight, has good air permeability, and will not form acne due to clogged pores; It has good moisturizing properties and can also promote the absorption of nutrients from other skin care products.

Washing clothes with hard water is not only difficult to wash, but also the fibers of the clothes will become hard and brittle, and the smell of detergent will remain. Using soft water to clean furniture can not only save a certain amount of housework time, but also extend the life of furniture.

The use of soft water can effectively protect household appliances such as water heaters, humidifiers, steam irons, etc. from being troubled by scale, saving energy and prolonging the service life of electrical appliances.