water hardness classification

Removal of Temporary Hardness..

Water is described as being 'hard' if it does not lather readily with soap. 'Soft water', on the other hand, is described as the one, which lathers readily with soap. Chemically, natural water is never pure and contains varying amounts of the dissolved impuri..

It is known that soap is the sodium salt of stearic acid (C 1 7 H 3 5 COO - Na + , sodium stearate). When soap is added to hard water it reacts with the calcium and magnesium ions present in hard water. This forms an insoluble calcium or magnesi..

Temporary hardness in water can be easily removed by boiling. On boiling, calcium/magnesium bicarbonate decomposes to give calcium/magnesium carbonate, which is insoluble in water. Therefore, it precipitates out...

Water is said to be permanently hard when it contains sulphates and chlorides of calcium and magensium. Water becomes permanently hard when it passes over the rocks, which contain sulphates or chlorides of calcium and magnesium to form insoluble calcium bica..

All metals are hard except sodium and potassium, which are soft and can be cut with a knif..

The hard seed coat can cause dormancy in plants i) By being impermeable to water the impermeability of seed coat to water and oxygen does not allow the seed to germinate. ii) In certain wild plants the hard seed coat acts as a physical barrier to the expansio..

The hardness of metals is due to the strength of the metallic bond. In general, the strength of a metallic bond depends upon: The greater the number of valence electrons for delocalisation the stronger is the metallic bond. Smaller the size of the kernel of metal atom, greater is th..

Choose the matrix which shows the information about the collection of books. Hard back: 11 medicine, 17 engineering, 3 arts. Paper back: 20 medicine, 7 engineering, 11 arts. H: Hard back P: Paper back M:Medicine E: Engineering A: Arts => H P M E A (..

Which graph represents the height of a football thrown up in the air from a hard flat ground until it comes to rest? => Graph 3 or Graph 1 or Graph 2 or None of the above..