Hard water in life mainly refers to water containing a certain amount of calcium and magnesium ions. Such water not only affects people's health, but also affects industrial production. All raw water used in many industries needs to be softened. Many friends are asking about the principle of soapy water testing hard water and soft water. Below is the Chengdu famous membrane water soft water treatment equipment manufacturer to share professional knowledge with you.
The principle of testing soft water and hard water with soapy water is: the main ingredient of soapy water is sodium stearate (C17H35COONa), hard water contains more calcium and magnesium ions, which react with soapy water to produce calcium stearate and magnesium stearate ((CH3(CH2)16COO)2Ca) precipitation, soft water contains less calcium and magnesium ions, so it can be used to test soft water and hard water.
Reaction principle: 2CH3(CH2)16COO(-)+Ca(2+)==(CH3(CH2)16COO)2Ca
Method 1. Take a cup of hot water and pour it into soapy water. If the foam appears on the water surface is soft water, if the scum appears on the water surface is hard water. The more scum there is, the hardness of water will be .
Method 2. You can also heat it with a beaker to leave more scale on the wall of the cup. Because hard water is water containing more soluble calcium and magnesium substances, after heating, these soluble calcium and magnesium substances are converted into insoluble substances, and more impurities precipitate in hard water. The more impurities, the greater the hardness of the water.
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