If one of the reactants is present in large excess, the reaction is more appropriately described as the dissociation of acetic acid in liquid ammonia or of ammonia in glacial acetic acid. Many salts give aqueous solutions with acidic or basic properties. This is termed hydrolysisand the explanation of hydrolysis reactions in classical acid—base terms was somewhat involved.
For example, hydrolysis of aqueous solutions of ammonium chloride and of sodium acetate is represented by the following equations:.
The sodium and chloride ions take no part in the reaction and could equally well be omitted from Album) equations. The reverse reactions simply represent, respectively, the neutralization of aqueous ammonia by a strong acid and of aqueous acetic acid by a strong base.
A superficially different type of hydrolysis occurs in aqueous solutions of salts of some metals, especially those giving multiply charged cations. For example, aluminum, ferric, and chromic salts all give aqueous solutions that are acidic. This behaviour also can be interpreted in terms of proton-transfer reactions if it is remembered that the ions involved are strongly hydrated in solution. In a solution of an aluminum saltfor instance, a proton is transferred from one of the water molecules in the hydration shell to a molecule of solvent water.
In the reaction of a Lewis acid with a base the essential process is the formation of an adduct in which the two species are joined by a covalent bond; proton transfers are not normally involved. If both the Lewis acid and base are uncharged, the resulting bond is termed semipolar or coordinateas in the reaction of boron trifluoride with ammonia:. Frequently, however, either or both species bears a charge most commonly a positive charge on the acid or a negative charge on the baseand the location of charges within the adduct often depends upon the theoretical interpretation of the valences involved.
Examples are:. In fact, reactions such as the simple adduct formations above often are formulated more correctly as replacements. For example, if the reaction of boron trifluoride with ammonia is carried out in ether as a solvent, it becomes a replacement reaction :. Similarly, the reaction of silver ions with ammonia in aqueous solution is better written as a replacement reaction:.
Furthermore, if most covalent molecules are regarded as adducts of often hypothetical Lewis acids and bases, an enormous number of reactions can be formulated in the same way. Opinions differ as to the usefulness of this extremely generalized extension of the Lewis acid—base-adduct concept. The reactions of anhydrous oxides usually solid or molten to give salts may be regarded as examples of Lewis acid—base-adduct formation. For example, in the reaction of calcium oxide with silica to give calcium silicate, the calcium ions play no essential part in the process, which may be considered therefore to be adduct formation between silica as the acid and oxide ion as the base:.
A great deal of the chemistry of molten-oxide systems can be represented in this way, or in terms of the replacement of one acid by another in an adduct. Acid—base reaction. Article Media. Info Print Print. Mineral-rich alkaline water is touted by many for its perceived health benefits and fresh spring water taste. Water becomes acidic when it combines with carbon dioxide during the process of precipitation. During the hydrologic cycle, water from sources like the ocean, lakes, and streams evaporate.
As the moist air rises, it cools and condenses into water vapor, creating clouds. This process is a natural form of water filtration. When water evaporates, it is stripped of water hardness, bacteria, and minerals.
The water distillation process mimics this principle to purify water. Since all of the minerals have been vaporized, this water is now soft and acidic. This forms a weak carbonic acid and lends water a mild acidity. The average pH of rainwater is around 5. When it hits the earth and seeps through layers of rock and sediment, the pH will adjust depending upon the environmental conditions it encounters.
If the rain is falling on calcium-rich limestone, it will absorb high mineral content and likely become hard water. However, if it seeps through a rock bed of something like granite, the water will stay acidic. Metamorphic and igneous rocks lack the calcium to buffer the pH and neutralize the acid in the water. This means many wells are likely to have acidic water, as they are often accessing shallow groundwater for their water supplies.
Water can also become acidic if from chemical runoffs or mine drainage sites. Acidic water is extremely corrosive and destroys household plumbing. The Album) properties of acid water dissolve the copper out of your pipes, leaving blue-green stains on your drains, in your bathtubs and sinks, and around your faucets.
This is an indication that serious damage is transpiring within your plumbing system, as the acidity of the water is eroding the copper out of your pipes.
If left unattended, pinhole leaks can spring and cause water damage. If these leaks emerge behind a wall, serious flooding can occur, leaving you with considerable damages to repair.
If you have plastic water tubing in your home like PEX or PVCthe acidic water will have a less corrosive effect on plumbing.
However, acidic water also wreaks havoc on water heaters and hot water appliances. The increase in temperature actually amplifies the corrosive characteristics of the water, leading to damage and premature failure of water heaters and appliances. The other significant problem acidic water presents is leaching. As the acid water flows through the metal pipes, it leaches the metal ions from the pipes and introduces them to your water supply.
This means the water can potentially contain levels of iron, manganese, copper, zinc, and lead. Drinking elevated levels of heavy metals can be toxic, especially lead. Iron and copper discolor water and leave unsightly stains on your plumbing fixtures and in your sinks and bathtubs. If the acidic water is leaching heavy metals into your water, acid water can pose health risks.
Exposure to high levels of zinc and copper leads to gastrointestinal upset, including nausea, vomiting, and diarrhea. Extended consumption of copper-heavy water can cause serious health complications, like gallstones, kidney stones, neurological damage, and even kidney and liver failure.
Lead is an extremely dangerous heavy metal to consume, especially for children. Lead exposure can cause cognitive impairment, memory problems, stunted development, and seizures. In adults, exposure to lead can cause high blood pressure, kidney and nervous system diseases, miscarriages and stillbirths, strokes, and even cancer.
The acidity of your water will dictate the method of acid neutralization required to raise your pH to a neutral value. There are several methods, each with varying strength, employed to eliminate acid water. The most common way to attack acidic water is with a whole-house acid neutralizer. Acid neutralizers usually use calcite to raise the pH of the water before it enters your household plumbing and wreaks havoc on your pipes.
Water is a universal solvent, and upon contact with the calcite media, it will begin to dissolve it, Album). This introduces calcium and alkalinity to the water, raising pH and neutralizing the acidity. In addition to being inexpensive, calcite is self-limiting. This means calcite only acts to elevate the acidic water to neutral, non-corrosive status and does not run the risk of overcorrection. However, calcite also has basic limitations.
Its efficacy is heavily reliant on the amount of contact time the water has with the media. If water is churned through the tank at a rapid pace, the pH adjustment will be minimal.
If your water has a pH level of around 5. A calcite and Corosex combination has the ability to raise pH around a point and a half. However, Abudantly Watering by Acid - Disguster (4) - Acts Of Mortification (CD calcite, Corosex can quickly overcorrect if too great a quantity is added. Furthermore, too much magnesium oxide can produce unfortunately side effects. Just like milk Album) magnesia, too much magnesium oxide can produce a laxative effect.
It goes without saying that it is best to use the Corosex media judiciously and avoid that outcome. Acidic water with a pH level in the low fives or high fours presents a unique challenge.
No longer is an acid neutralizer tank system with calcite or Corosex a viable solution. Water this acidic demands a chemical injection system to raise pH to a comfortably neutral zone. This uses a chemical pH adjuster called soda ash. These systems use peristaltic pump technology to inject the water with a dissolved mixture of the soda ash before it enters your home and runs its ruinous course of corrosion.
Chemical injection systems are high maintenance and require dedicated attention. However, if your water is that acidic, it is necessary to protect your health and your home. If the pH is as low as four, the only acid neutralizer you can use is caustic soda.
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