Acid Bases and Salts
Check us out at http://www.tutorvista.com//videos Acids In everyday life we deal with many compounds that chemists classify as acids. For example, orange juice and grapefruit juice contain citric acid. These juices, and others, also contain ascorbic acid, a substance more commonly known as Vitamin C. Salads are often flavored with vinegar, which contains dilute acetic acid. Boric acid is a substance that is sometimes used to wash the eyes. In any chemistry laboratory, we find acids such as hydrochloric acid, sulfuric acid, and nitric acid. These acids are called mineral acids because they can be prepared from naturally occurring compounds called minerals. Mineral acids are generally stronger than household acids, and should be handled with great care because they can burn skin and clothing. Bases: Ammonium hydroxide, or ammonia water, is very irritating to the nose and the eyes. This substance, called a hydroxide, or a base, is often used in the home for cleaning because bases generally dissolve grease. Milk of magnesia (magnesium hydroxide), which is used as an antacid, is a base; lye (sodium hydroxide), which is used in the manufacture of soap, is another familiar example of base. Bases are ionic compounds containing metal ions and hydroxide ions. For example, sodium hydroxide contains sodium ions and hydroxide ions. When sodium metal is placed in water, sodium hydroxide is formed and hydrogen gas is released. Since the formula for water can be written as HOH instead of H2O, the reaction involves single replacement: 2 Na (s) + 2 HOH (l) ?????2 NaOH (aq) + H2 (g) Salts: Many chemical compounds may be classified as salts. The salt most familiar to all of us is table salt -- sodium chloride. Baking soda is the salt sodium bicarbonate. Magnesium sulfate, also called Epsom salts, is often found in the home In general, salts are ionic compounds that are composed of metallic ions and nonmetallic ions. For example, sodium chloride is composed of metallic sodium ions and nonmetallic chloride ions. Some salts are composed of metallic polyatomic ions and nonmetallic polyatomic ions (ammonium nitrate is composed of ammonium ions and nitrate ions).