You may look back at the passage while you answer the questions. Work carefully but rapidly. There are 3 passages and 40 sets of questions. The answer is 40 with a letter A in front of it. So the circle with A in the center should be blackened in the answer row for sample question 1.
Acids contain many hydrogen atoms.
Some acids, like sulfuric and hydrochloric acid, can be very dangerous. However, hydrochloric acid, as a component of stomach acid, is used in digestion. Bases contain a combination of hydrogen and oxygen atoms called hydroxyl groups. Household cleaning agents such as ammonia, borax, lye, and detergents are common examples of bases. Many different kinds of acids and bases are used by scientists.