Lesson Worksheet: Indicators and pH Science
In this worksheet, we will practice using indicators to measure the pH of different substances.
Car batteries and lemons both contain different types of acids. Which of the following statements about these two acids is correct?
- AThe acid in car batteries has a higher pH than the acid in lemons and would turn universal indicator paper red.
- BThe acid in car batteries has a lower pH than the acid in lemons and would turn universal indicator paper blue.
- CThe acid in car batteries has a lower pH than the acid in lemons and would turn universal indicator paper red.
- DThe acid in car batteries has a higher pH than the acid in lemons and would turn universal indicator paper blue.
- EThe acid in car batteries has a lower pH than the acid in lemons and would turn universal indicator paper green.
Which of the following foods found in a kitchen could be used as an indicator for acids and alkalis?
- ABrown bread
- BBeige lima beans
- CRed cabbage
- DGreen lettuce
- EWhite flour
When measured, milk has a pH of 6.6. What does this tell you about the acidity or alkalinity of milk?
- AIt is strongly acidic.
- BIt is strongly alkaline.
- CIt is weakly alkaline.
- DIt is neutral.
- EIt is weakly acidic.
Each beaker in the diagram contains an unknown solution and a few drops of universal indicator.
Place the five beakers in the correct order from most acidic to most alkaline.
Blood plasma is almost colorless. It is the red blood cells that give it a characteristic red color. If the pH of the plasma is 7.4, which of the following colors would likely be seen if it was tested using a universal indicator?
What is a solution said to be if it has a green color once a few drops of universal indicator solution are added to it?
There are many different types of indicators that professional chemists use in their laboratories. One of these indicators is called bromothymol blue. Bromothymol blue turns yellow in the presence of an acid and blue in the presence of an alkali.
What color would you expect to see when a few drops of bromothymol blue are added to a solution of sodium hydroxide?
What color would you expect to see when a few drops of bromothymol blue are added to a solution of sulfuric acid?
What color would you expect to see when a few drops of bromothymol blue are added to water?
The table below gives some naturally occurring indicators that have been extracted from plants as well as the colors that they turn in the presence of dilute acids and alkalis.
|Indicator||Red cabbage||Curry powder||Purple peonies|
|Color with Acid||Red||Yellow||Pink|
|Color with Alkali||Green||Red||Purple|
A student takes an unknown solution and is told by the teacher that the pH of the solution is either 3, 7, or 12. The student adds the red cabbage indicator solution, which turns green. What color would the solution have turned had the student added the indicator made from the petals of the purple peonies?
Which column in the table correctly shows the color changes that take place when water is tested by the indicator papers listed in the table?
|Indicator Paper||Column 1||Column 2||Column 3||Column 4||Column 5|
|Red litmus||No change||Red||Red||No change||Blue|
|Blue litmus||No change||Blue||Blue||No change||Red|
- AColumn 3
- BColumn 4
- CColumn 1
- DColumn 2
- EColumn 5
In which section of the pH scale shown in the diagram might you expect to find a solution that is strongly acidic?
- ASection 5
- BSection 3
- CSection 4
- DSection 2
- ESection 1