What is Acid Rain?
The majority of people consider rain to be an undamaging weather occurrence. However the increase in acidity of rain is both unsafe and damaging.
In order to fully understand the term acidity, it is essential to know something about the pH scale. This scale has a range of 0 to 14, with 7 being neutral. Anything below 7 (0-6) is known to be acidic and anything above 7 (8-14) is alkaline. A change in only one unit is equal to a tenfold increase in the strength of the acid or base. Therefore a unit change from pH 6 to pH4 is equal to a 10 x 10 increase in it acidity.
Taking the above into consideration, it is easy to see how the normal phenomenon “rain” is becoming more and more acidic as its pH has dropped from around 6and 7 to about 4.3and 5.3.This occurrence is known as Acid
Rain and was first noted in1852 by the English chemist called Robert Angus Smith.
acid rain in other words is the term used to describe rainfall that has a pH level below5.6. It is a form of air pollution that is currently a theme of huge debate due to its wide spread damages. It is responsible for the destruction of thousands of lakes and streams in the United States, Canada and parts of Europe.
How Acid Rain is formed
The two most important primary sources of acid rain are sulphur dioxide (SO2) and oxides of nitrogen (NOx).
The Essay on Rain & Acid Rain
Nancy Vinia A. Galang II – BSITE Rain and Acid Rain: An Overview Rain is essential to our world. If there is no rain, we may experience drought and many will be affected. However, there is another type of rain that is called acid rain. This type of rain can bring negative effects in our world. Here, we are going to know what makes these two very different from each other. Rain are water drops ...
Sulphur is a colourless, pungent gas produce during the combustion of fossil fuels containing sculpture. A variety of industrial processes such as the production of steel and iron and crude oil processing produce this gas. This gas is also emitted into the atmosphere by natural means. Ten percent of the sculpture in the atmosphere comes from volcanoes, sea spray, plankton and decomposing vegetation.
The other gas primarily accountable for the formation of acid rain is nitrogen oxide. The term ‘oxides of nitrogen’ describes any compound of nitrogen with any amount of oxygen atoms. The only oxides of nitrogen are nitrogen monoxide and nitrogen dioxide. These gases are produced by firing processes at very high temperatures (vehicle) and chemical industries. There are natural processes such as forest fires, volcanoes and bacterial action in soil that also emit nitrogen oxides. Transportation and industrial combustion also contribute to the emissions of nitrogen oxides.
The acidity of acid rain does not only depend on the release levels of these gases but also on the chemical combination sulphur dioxide and nitrogen oxides interrelate in the atmosphere. Both gases undergo a few chemical reactions before they become the acids present in acid rain. The two main phases are the gas phase and the aqueous phase.
As far as sulpur dioxide is concerned there is a range of possible reactions that may lead to the oxidation of the gas in the atmosphere each having a different degree of success. One option is the photooxidation of the gas by ultraviolet light. This reaction has been found to be an unimportant supplier to the creation of sulphuric acid.
Another route that is more common is the one where sulphur dioxide is oxidized to form a sulphite ion.
SO2 (g) + o2 (g) à SO32-
After this the sulphite ion forms sulphuric acid when it comes into contact with the moisture in the atmosphere.
SO32- +H2O (l)à H2SO4 (aq)
This reaction takes place quickly therefore the construction sulphur dioxide in the atmosphere is thought to lead to this kind of oxidation and form sulphuric acid. The photooxidation method is much slower due to the absence of a catalyst.
The Term Paper on Acid Rain Deposition Sulphur Dioxide
... fossil fuels causes sulphur dioxide and nitrogen, which happens to be the major causes of acid rain. These gases are emitted into the atmosphere where they ... AND ANSWERS 1) Explain dry acid deposition. Sometimes the acids can be transformed chemically into sulphur dioxide gases into sulphur and nitrogen salts in which they are ...
A third reaction for sulphur dioxide to become sulphuric acid is by the oxidation by ozone. All the reactions mentioned to this point are gas state reactions. In the aqueous phase sulphur dioxide exists as three kinds:
[S(IV)]à[SO2(aq)] + [HSO32]+[SO32]
There is a dissociation that consists of two parts:
SO2 (aq)à H++HSO3-
HSO3- (aq)àH+ + SO32-
The oxidation of aqueous sulphur dioxide depends on catalysts like iron and manganese.
The oxidation of sulphur dioxide is most widespread in clouds and particularly in greatly polluted air where there are abundant amounts of ammonia and ozone, which act as catalysts in the formation of sulphuric acid from sulphur dioxide. However, not all the sulphur dioxide becomes sulphuric acid, as a lot of it floats up into the atmosphere and is transported to other areas and returns to earth unchanged.
Nitrogen oxides like sulphur dioxide rise into the atmosphere and are oxidized in clouds to form nitric acid. Very polluted clouds where traces of manganese, hydrogen peroxide and iron are present provide catalysts for theses reactions. Nitrogen oxides are mainly emitted into the atmosphere by vehicle exhausts. They react with water to form nitric acid in the atmosphere.
NO2 (g)+H2O (l)àHNO3 (aq)+HNO2(aq) [gas phase]
In the aqueous phase there are three equilibria that have to be considered for the oxidation of nitrogen oxide.
* 2NO2(g)+H2O(l) 2H++NO3- +NO2-
* NO (g)+NO2(g)+H2O (l) 2H+ +2NO2-
* 3NO2(g)+H2O(l) 2H+ +2NO3-+2NO(g)
The limited pressures of nitrogen oxides present in the low atmosphere, and the low solubility of nitrogen oxides limit the above reactions. There is an increase in the rate of the reactions only with the use of metal catalysts like in the case of the aqueous oxidation of sulphur dioxide.
The effects of Acid Rain
Scientists have noticed that over the years some forests seem to be growing more and more slowly for no obvious reason. After the collection of information on the chemistry and the biology of the forests it has been proved that this is due to acid rain.
When acid rain falls, the acidic rainwater dissolves the nutrients and helpful materials from the soil. These minerals are then washed away before trees other plants can use them to grow. The acid rain also helps release toxic substances such as aluminum into the soil. This is o due to the fact that metals like this are bound to the soil under normal conditions, but the added dissolving act of hydrogen ions causes rocks and small bound soil particles to break down. When acid precipitation is regular leaves are likely to lose their waxy protective coat. This loss makes the plant open to any disease. When the leaves are damaged the plant cannot produce adequate food energy for it to survive. When the plant is weak it is defenseless to disease, insects that may kill it.
The Term Paper on Acid Rain 10
Acid rain is exactly what it suggests- rain that is acidic. The definition of 'acid rain' is rain with a pH of below 5.6. Rain becomes acidic because of gases that dissolve in the rain. Approximately 70% of acid rain is a result of dissolved sulfur dioxide (SO2) which forms Sulfuric Acid. The remaining 30% or so comes from various Nitrogen Oxides (mostly NO2 and NO3 which has collectedly adopted ...
Acid rain also affects aquatic organisms. It enters lakes in several ways but the most common route is when it is drained through sewage systems that lead to lakes. The euphoric acid present in acid rain interferes with the fish’s’ ability to take in oxygen, salts and nutrients. Acid molecules cause the formation of mucus to form in their gills not allowing them to absorb oxygen well. Additionally the low pH level does not allow the calcium levels of the fish to be maintained causing the eggs during reproduction to be weak and brittle. Sometimes when acid rain runs off the land it carries some fertilizers along into the lakes .The fertilizers induce the growth of sea plants causing eutrophication.
Apart from natural ecosystems, acid rain also affects man-made materials and buildings. Limestone, marble and sandstone are all very easily dissolved by acid rain. Textiles, paints, metals and ceramics can readily be decayed. Man-made materials are slowly depreciated with normal rainfall but acid rain speeds up this process.
However, most importantly acid rain can affect the health of human beings. It harms us via the atmosphere or through the soil from where we get our food. Acid rain causes the release of toxic metals that may be absorbed by drinking water, crops or animals that may later consumed by humans. These could cause nerve damage to children or acute brain damage or even death.
Acid precipitation is very harmful to the respiratory system. Sulphur dioxide and nitrogen oxide secretion may lead to dry coughs, asthma, headaches, eye, and nose and throat irritation. It has the ability of making breathing very difficult and may give rise to diseases, which could possibly lead to death.
The Term Paper on Acid Rain 16
... or acid rain as it is commonly known, occurs when emissions of sulfur dioxide (SO2) and oxides of nitrogen (NOx) ... will reduce sulfates, nitrates, and ground level ozone (smog), leading to improvements in public health. -------------------------------------------------- ---------------------- -------------------------------------------------- ---------------------- Acid rain primarily affects ...
How acid rain can be prevented
Sulphur dioxide in the atmosphere can be reduced either by fitting desulphurization plants to power stations or by changing the fuel or the way it is burned. The main suppliers of nitrogen oxides are motor vehicles and industries. Flue gases can be dealt with so that most of the nitrogen oxides are removed. Catalytic converters can be installed in the exhaust systems of vehicles. These convert nitrogen oxides, carbon dioxides and unburned hydrocarbons into a cleaner state.
Conclusion
Overall, acid rain is a problem that should not be ignored. This occurrence ruins anything it comes into contact with. By affecting the environment acid rain affects humans on the long run as well. What we can do, to reduce the emission of gases that cause acid rain is to reduce the use of fossil fuels. Walking and public transportation can reduce tons of nitrogen oxide emissions. The use of less energy is beneficial to the atmosphere as energy comes from fossil fuels, which may lead to acid rain.
