pH Indicators and Their Functions

The video tutorial explains how to use an acid-base indicator chart from a data booklet to determine the pH of solutions. It covers the use of methyl orange and phenolphthalein as indicators, demonstrating their color changes in different pH environments. The tutorial also includes a practical example with Solution X, showing how to narrow down the pH range using multiple indicators.

What is the primary purpose of an acid-base indicator chart?

• To identify the chemical formula of a solution

• To calculate the concentration of a solution

• To determine the pH range of a solution using color changes

• To measure the temperature of a solution

What color does methyl orange turn in a solution with a pH less than 3.2?

• Yellow

• Green

• Red

• Blue

In what pH range does methyl orange change from red to yellow?

• 7.0 to 8.0

• 5.0 to 6.0

• 3.2 to 4.4

• 1.0 to 2.0

What happens to phenolphthalein in a solution with a pH less than 8.2?

• It turns pink

• It turns yellow

• It becomes colorless

• It turns blue

What color does phenolphthalein turn in a solution with a pH greater than 10.0?

• Red

• Colorless

• Pink

• Yellow

Which indicator would you use to determine if a solution has a pH greater than 4.4?

• Methyl red

• Phenolphthalein

• Bromothymol blue

• Methyl orange

What does a yellow color in bromothymol blue indicate about the pH of a solution?

• The pH is greater than 7.0

• The pH is greater than 8.0

• The pH is less than 6.0

• The pH is exactly 7.0

If methyl red turns red in a solution, what can be inferred about the pH?

• The pH is greater than 8.0

• The pH is exactly 5.0

• The pH is less than 4.4

• The pH is greater than 6.0

How can multiple indicators help in determining the pH of an unknown solution?

• They change the chemical composition of the solution

• They narrow down the pH range to a more accurate level

• They offer a broad pH range

• They provide a single pH value

What is the benefit of using multiple indicators in pH determination?

• It increases the temperature of the solution

• It provides a more accurate pH range

• It decreases the concentration of the solution

• It changes the color of the solution