Chemical indicators

1. What are chemical indicators?

• a. Substances that only change color in acidic solutions

• b. Substances that change color differently in acidic and alkaline mediums

• c. Substances that only change color in neutral solutions

• d. Substances that only change color in alkaline solutions

2. What happens to blue litmus paper in an acidic medium?

• a. It stays blue

• b. It turns purple

• c. It turns red

• d. It becomes colorless

3. In a neutral medium, what happens to both red and blue litmus strips?

• a. They both turn red

• b. They both turn blue

• c. Their colors remain unchanged

• d. They both become colorless

4. What must be done to test gases with indicator strips?

• a. Heat the strips first

• 
  b. Wet the strips with water

• c. Dry the strips completely

• d. Freeze the strips

5. What happens when chlorine gas interacts with litmus strips?

• a. Turns them red

• b. Turns them blue

• c. Makes them wet

• d. Bleaches both strips

6. How do Hydrangea flowers appear when planted in acidic soil?

• a. They appear red

• b. They appear yellow

• c. They appear purple

• d. They appear blue

7. Which type of gases do not change the color of indicators?

• a. All basic gases

• b. All acidic gases

• c. Gaseous elements (except chlorine)

• d. All gases containing nitrogen