Acid-Base Reactions and Indicators

The video tutorial demonstrates a neutralization reaction using sodium hydroxide, hydrochloric acid, and phenolphthalein. Initially, sodium hydroxide is prepared in a conical flask, and phenolphthalein is added, turning the solution pink. Hydrochloric acid is then added drop by drop until the pink color disappears, indicating neutralization. Further addition of sodium hydroxide causes the pink color to reappear. The reaction results in the formation of sodium chloride and water, illustrating the concept of neutralization.

What materials are required to perform the neutralization reaction experiment?

• Ammonia, vinegar, and methyl orange

• Sulfuric acid, sodium bicarbonate, and litmus paper

• Dilute hydrochloric acid, sodium hydroxide solution, and phenolphthalein

• Sodium chloride, water, and phenolphthalein

What is the initial color of the sodium hydroxide solution before adding phenolphthalein?

• Colorless

• Yellow

• Pink

• Blue

What happens to the sodium hydroxide solution when phenolphthalein is added?

• It remains colorless

• It turns blue

• It turns pink

• It turns green

What is the role of phenolphthalein in the experiment?

• It neutralizes the acid

• It is an indicator

• It is a catalyst

• It acts as a base

What is observed when hydrochloric acid is added drop by drop to the sodium hydroxide solution?

• The pink color remains initially

• The solution becomes cloudy

• The pink color disappears immediately

• The solution turns blue

Why does the pink color in the solution not disappear immediately after adding hydrochloric acid?

• Because the solution is acidic

• Because there is still sodium hydroxide present

• Because the phenolphthalein is exhausted

• Because the solution is neutral

At what point does the pink color in the solution disappear?

• When more sodium hydroxide is added

• When all the phenolphthalein is used up

• When the solution becomes neutral

• When the solution becomes acidic

What happens when more sodium hydroxide is added to the acidic solution?

• The pink color reappears

• The solution remains colorless

• The solution turns blue

• The solution becomes cloudy

What are the products formed when sodium hydroxide reacts with hydrochloric acid?

• Sodium sulfate and water

• Sodium chloride and water

• Sodium bicarbonate and water

• Sodium acetate and water

What is the term used to describe the reaction between an acid and a base?

• Reduction

• Oxidation

• Neutralization

• Precipitation