Answers to Lab Questions on Measuring pH Values

Part II4. Acids and bases found around the homeAcidsVinegarLemon juiceBattery acidTomato juiceBasesSoapBaking powderToothpasteCement5. Acids have the following properties in common;They have a sour tasteThey corrode metal surfacesThey have low pH values below 7.6. Bases have the following features in common;They taste bitterThey have a soapy feelThey have pH values above 77. Acid rain and its impactAcid rain is rain that has pH lower than 6.0, which often falls as low as 3, because of the presence of sulfuric acid and nitric acid in the rainwater. Nitric oxide and sulfur (IV) oxide react with rainwater to form nitric acid and sulfuric acid respectively. This causes the rainwater to become highly acidic. The change in acidity of rainwater from 6.0 to 3.0 makes acid rain about 1000-fold more acidic than normal rainwater. Sulfur dioxide forms from burning of coal while nitric oxide comes from automobile exhaust gases.Acid rain corrodes iron sheets, limestone statues, and even plant leaves. It also kills aquatic animals like fish and frogs. Moreover, acid rain living organisms never grow well in acidic conditions; so, acid rain threatens the life of both aquatic and terrestrial plants and animals. Lakes that have industries and factories around them are the ones most affected by acid rain.8. When a lake receives acid rain for a long time;Acidity drops from 6 to 3.That means the pH has changed by 3 units.For every unit decrease in pH, the acidity increases 10 times.Therefore, a decrease of 3 units will increase the acidity by 10 x 10 x 10= 1000 times more acidic.Negative Impact on Environment: The low pH values resulting from acid rain kills aquatic animals and plants.