Exploring the pH Scale and Indicators

This video tutorial explores the pH scale and indicators used to determine if a substance is acidic, neutral, or alkaline. It explains the use of litmus paper, which changes color to indicate acidity or alkalinity, and the universal indicator, which provides a more detailed pH value. Examples of substances with different pH levels are given, and the use of pH meters for precise measurements is discussed.

What does the pH scale measure?

• Acidity or alkalinity of a substance

• Temperature of a solution

• Volume of a liquid

• Mass of a substance

What color does red litmus paper turn in alkaline conditions?

• Blue

• Red

• Yellow

• Green

What does blue litmus paper indicate when it turns red?

• Neutral condition

• Acidic condition

• Alkaline condition

• No change

Which pH value represents a neutral solution?

• 7

• 10

• 0

• 14

What is the pH value of seawater?

• About 8

• 13

• 5.5

• 7

What is the main use of a universal indicator?

• To measure the volume of liquids

• To determine the pH value of solutions

• To change the color of solutions

• To measure the temperature of solutions

Which substance has a pH of approximately 5.5?

• Seawater

• Bleach

• Acid rain

• Stomach acid

What is the pH range for acidic solutions?

• 0 to 6

• 7 to 14

• 0 to 7

• 8 to 14

What does a pH meter specifically measure?

• pH value to two decimal places

• Temperature fluctuations

• Electrical conductivity

• Color changes in solutions

Which tool provides the most precise pH readings?

• pH meter

• Thermometer

• Universal indicator

• Litmus paper