Acid-Base Reactions and pH

The video demonstrates the use of pH paper to observe the effects of adding a strong acid (hydrochloric acid) and a strong base (sodium hydroxide). Initially, distilled water with a neutral pH of 7 is applied, showing no change. When hydrochloric acid is added, the pH paper turns red, indicating a pH of 0. Adding sodium hydroxide results in a pH of 14, turning the paper blue. As the acid and base meet, they neutralize each other, forming a yellow line that indicates a neutral pH of 7, resulting in salt water. The video concludes with a summary of the neutralization reaction.

What is the pH of distilled water?

• 1

• 14

• 7

• 0

What color does the pH paper turn when hydrochloric acid is applied?

• Yellow

• Red

• Green

• Blue

What is the pH of a one molar solution of sodium hydroxide?

• 0

• 7

• 14

• 1

What is the color of the line formed when hydrochloric acid and sodium hydroxide meet on the pH paper?

• Red

• Yellow

• Blue

• Green

What is produced when hydrochloric acid and sodium hydroxide neutralize each other?

• Carbon dioxide

• Oxygen

• Salt water

• Hydrogen gas

What is the pH of the solution after neutralization?

• 1

• 14

• 7

• 0

What is the final observation about the pH paper after the reaction?

• It remains red

• It turns blue

• It turns black

• It becomes neutral