Hard water is water that has high mineral content (in contrast with “soft water”). Hard water is generally not harmful to one's health, but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that handles water.
As water moves through soil and rock, it dissolves very small amounts of minerals and holds them in solution. Calcium and magnesium dissolved in water are the two most common minerals that make water "hard."
Water described as “hard” is high in dissolved minerals, specifically calcium and magnesium. Hard water is not a health risk, but a nuisance because of mineral buildup on fixtures and poor soap and/or detergent performance.
Hard water is not a health risk. However, the mineral buildup on fixtures and pipe, and poor detergent performance can become a nuisance.
In the home environment, hard water requires more soap and synthetic detergents for laundry and washing. It takes half as much soap for cleaning with soft water. Hard water and soap combine to form "soap scum" that can't be rinsed off, forming a “bathtub ring” on all surfaces, and it dries leaving unsightly spots on dishes.
Using soap on the body in hard water can cause the formation of a scum often referred to as “curd.” Curd remains on the skin even after rinsing, clogging pores and coating body hair. Curd can serve as a medium for bacterial growth, causing nappy rash, minor skin irritation and skin that looks dry and continually itches.
In the laundry, hard water leaves soap curd and detergent deposits on fabrics. This dulls colors and gives a grey or yellow appearance to white fabrics. Also hard water soap curd clings to fabric fibers, causing threads to become brittle and shortening the life of the material.
Hard water wastes soap and synthetic detergents.
Hard water leaves unsightly soap scum rings in the bathtub.
Hard water spots and streaks glassware and dishes.
Hard water makes bathing more difficult for skin and hair.
Hard water builds up scale deposits in all water-using appliances and clogs hot water pipes.
Even more important to the homemaker and to his/her entire family, hard water hampers good grooming efforts.
Burets are used primarily for titration, to deliver one reactant until the precise end point of the reaction is reached.
For large-scale municipal operations, a process known as the "lime-soda process" is used to remove Ca2+ and Mg2+ from the water supply. Ion-exchange reactions, similar to those you performed in this experiment, which result in the formation of an insoluble precipitate, are the basis of this process. The water is treated with a combination of slaked lime, Ca(OH)2, and soda ash, Na2CO3. Calcium precipitates as CaCO3, and magnesium precipitates as Mg(OH)2. These solids can be collected, thus removing the scale-forming cations from the water supply.
Hardness is commonly confused with alkalinity. Alkalinity is a measure of the amount of acid (hydrogen ion) water can absorb (buffer) before achieving a designated pH. The problem relates to the term used to report both measures, CaCO3 in mg/l. Just as with hardness, mg/l CaCO3 alkalinity is a general term used to express the total quantity of base (hydrogen ion acceptors) present. If limestone is responsible for both hardness and alkalinity, these values will be similar if not identical. However, where sodium bicarbonate (NaHCO3) is responsible for high alkalinity it is possible to have low hardness and low calcium. Acid ground or well water has little or no alkalinity and can have low or high hardness.
Advantages of Using Soft Water:
• You will use less soap and other cleaning products.
• Reduce the difficult to clean "soap scum" and 'bathtub ring'
• Soap Scum stays on surfaces leaving unsightly spots on dishes, glass ware and flat ware.
• Heating hard water in the water heater, forms hardness scale. This scale plugs plumbing and builds up on the inside of water heaters, It can cause increased electric or gas bills, and may lead to early failure of the appliance with costly replacement necessary.
• Soap scum is difficult to remove and stays on your skin after bathing or showering. It clogs skin pores and coats hair. This residue may be a breeding ground for bacteria, and could cause diaper rash, rough, red hands, skin irritation and skin discomfort.
• Hardness minerals may cause unwanted taste in cooked foods such as vegetables and cause cloudy ice cubes.
Experts say that the levels of calcium found in hard water are unlikely to cause any increase in kidney stone formation and pose no health problems for the general public. In fact, not drinking enough water is a major contributing factor in kidney stone formation. Persons who have recurring kidney stones, or are on a calcium restricted diet, should consult their physician concerning their diet and liquid intake.