What chemical is responsible for water hardness?

Hardness is caused by compounds of calcium and magnesium, and by a variety of other metals.

What basic principles are involved in any water softening method?

When water containing calcium and magnesium flow across the resins in sodium form, they are exchanged with sodium which is released in water. This is the purpose of the softening process: the calcium and magnesium (their carbonates cause scale) are replaced with sodium, where the sodium carbonate is perfectly soluble.

What is hard and soft water in chemistry?

Hard water… is water that contains an appreciable quantity of dissolved minerals (like calcium and magnesium). Soft water… is treated water in which the only ion is sodium. On the other hand, soft water tastes salty and is sometimes not suitable for drinking.

What are salts responsible for hard water?

hard water, water that contains salts of calcium and magnesium principally as bicarbonates, chlorides, and sulfates. Ferrous iron may also be present; oxidized to the ferric form, it appears as a reddish brown stain on washed fabrics and enameled surfaces.

What is zeolite process of water softening?

In zeolite softening, water containing scale-forming ions, such as calcium and magnesium, passes through a resin bed containing SAC resin in the sodium form. In the resin, the hardness ions are exchanged with the sodium, and the sodium diffuses into the bulk water solution.

Which chemical is used for water softening?

Sodium hexametaphosphate (Na6P6O18), commercially called ‘calgon’ is used for water softening.

What is the pH of soft water?

For baking, the ideal is water with a pH of just below 7. Figure 23 pH Scale….77 Water Hardness and pH.

Type of Water	Hardness
Soft water	10-50 ppm
Slightly hard water	50-100 ppm
Hard water	100-200 ppm
Very hard water	Over 200 ppm

What causes hard water?

Hard water is water that has high mineral content (in contrast with “soft water”). Hard water is formed when water percolates through deposits of limestone, chalk or gypsum which are largely made up of calcium and magnesium carbonates, bicarbonates and sulfates.

What is zeolite process in chemistry?

i. A base exchange method of treating hard water, in which zeolites, contained in a tank, remove salts. The zeolite layer is regenerated by backflushing with brine.

What are zeolites in chemistry?

Zeolites are crystalline solids structures made of silicon, aluminum and oxygen that form a framework with cavities and channels inside where cations, water and/or small molecules may reside. They are often also referred to as molecular sieves.

What is the process of softening of water?

Softening is the process of removing the dissolved calcium and magnesium salts that cause hardness in water. It is achieved either by adding chemicals that form insoluble precipitates or by ion exchange. Chemicals used for softening include calcium hydroxide (slaked lime) and sodium…

How does a water softener system work?

A typical water-softening system removes calcium and magnesium ions from hard water and replaces them with sodium ions. Calcium and magnesium ions interfere with the action of household soaps and detergents, but sodium does not.

What happens to sodium ions in a water softener?

As hard water passes through a softener, the calcium and magnesium trade places with sodium ions (Figure 1). Sodium ions are held loosely and are replaced easily by calcium and magnesium ions. During this process, “free” sodium ions are released into the water.

What chemicals are used to soften water?

Water softening is achieved either by adding chemicals that form insoluble precipitates or by ion exchange. On a small scale, chemicals used for softening include ammonia, borax, calcium hydroxide (slaked lime), or trisodium phosphate, usually in conjunction with sodium carbonate (soda ash).