Question

4. What is demineralized water? Is it fit for drinking purposes?
Why hard water does not form lather with soap?​

Answer 1

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Demineralised water that has not been remineralized, or low-mineral content water – in the light of the absence or substantial lack of essential minerals in it – is not considered ideal drinking water, and therefore, its regular consumption may not be providing adequate levels of some beneficial nutrients.

Soap contains sodium salt from stearic acid. In soft water, this sodium dissolves easily, but in hard water, it binds to the minerals and produces insoluble calcium or magnesium stearate, also known as soap scum

Answer 2

Answer:

Demineralised or distilled water is not drinking purposes since it does not contain even useful minerals . Therefore, to make it useful for drinking purposes, useful minerals in proper amounts should be added to demineralised or distilled water. ... Therefore, even demineralized water is fit for drinking purposes.

Explanation:

Soft water lathers easily with soap but hard water does not. Soap reacts with hard water to form the calcium or magnesium salt of the organic acid in the soap. These salts are insoluble and form greyish soap scum, but no lather