Acid Rain and Alkalinity of the Lakes in Canada Essay

Acid Rain and Alkalinity of the Lakes in Canada - Essay Example In the same way, surrounding vegetations also determines the acidity or alkalinity of the lake, such as types of trees, soil, and decaying leaves. Humus (layers of decaying leaves) has rich organic matter and they produce acids similar to vinegar.Another determinant of lakes is its location and natural bases, that is, answer lies in geology. If the lake has surrounding of rocks containing limestone contain bases, then acids will be reduced (neutralized) by the natural bases and the pH of the lake will remain nearly the same. Calcite (CaCO3) greatly mitigates the effects of acid rain. Calcite is the principal mineral that makes up the rock limestone. For example, the case of sulfuric acid falling on limestone can be understood by the following reaction: The sulfuric acid is changed into mineral gypsum (CaSO4.H2O) and Carbon dioxide is released. Thus, lakes located on limestone terrains will not suffer the consequences of acid rain. On the other hand, rocks which contain granite contain has very little bases and is unable to neutralize the acidic ingredients. Eastern Canada is facing widespread acidification of lakes due to acid rain, and presence of granite rocks. In Ontario approximately 1200 lakes are dead.Acid rain refers to all types of precipitation - rain, sleet, fog, hail, snow that has a pH lower than the 5.6 average of rainwater. Note that the rain water is naturally slightly acidic due to equilibration with atmospheric carbon dioxide. The "pure" rain water's acidity is between pH 5.6-5.7, somewhat pH readings vary depending upon place to place and amount of other gases present in the air, such as nitrogen oxides and sulfur oxide. The pH scale refers to the free hydrogen ions (electrically charged atoms) in water and a number that ranges from 0 to 14. Seven is considered neutral, that is, neither acidic nor basic. Number less than seven are acidic and those higher it is basic or alkaline. The pH scale is logarithmic (base 10), and not linear. For example, pH 3 is 10 times more acidic than pH 4 and 100 times more than pH 5. The formation of acid in the acid rain is due to two kinds of air pollutants - sulfur dioxide (SO2) and nitrogen oxides (NOx). These pollutants react with gaseous water in the atmosphere to form sulfuric acid (H2SO4) and nitric acid (HNO3). The two-step process explains the formation of acid solutions by SO2. First the sulfur dioxide molecules react with water molecules and forms molecules of sulfurous acid: SO2(gas) + H2O(liquid) H2SO3(aq) Then the Sulfurous acid molecules reacts with water and produces an equilibrium with H+(aq) and hydrogen sulfite. Because the Sulfurous acid only partially ionizes into H+(aq) so it is considered as a weak acid: H2SO3(aq) + H2O(liquid) H+(aq) + HSO3(aq) Sulfur dioxide also reacts with oxygen or ozone and form sulfur trioxide: SO2(gas) + O2(gas) + 2SO3(gas) SO2(gas) + O3(gas) SO3(gas) + O2(gas) Then the sulfur trioxide reacts with the atmospheric moisture to form sulfuric acid: SO3(gas) + H2O(liquid) H2SO4(aq) The sulfuric acid which is a strong acid, completely ionizes in the atmospheric precipitation to release H+(aq) ions: H2SO4(aq) H+(aq) + HSO4-(aq) These aqueous hydrogen are responsible for the acidic effects in the acid rain. In Canada about 60% of pollution is caused by transportation emission. Car engines uses gasoline, which burn using air as a source of oxygen. Nitrogen is the primary component of air and under high temperature inside the car engine it forms the pollutant nitrogen monoxide (NO). Under sunlight a series of secondary reactions takes place and