Answer the following question

Experiment 10 - Red Cabbage Lab.docx

Experiment 10. Red Cabbage Chemistry

Student Name (Print):__________________________

Pre-lab Study Questions (Submit upon arrival for experiment)

Complete the following table:

[H3O+]	[OH-]	pH	pOH	Acidic/Basic/Neutral
2.35 10-3
	4.93 10-8
		8.32
			10.27
3.72 10-10
	1.00 10-7
		2.58
			5.26
1.00 10-3
	4.27 10-2
		8.00
			2.04

Experiment 10. Red Cabbage Chemistry

Student Name (Print):__________________________

I. Objectives

(1) Understand how pH indicators work

(2) Use red cabbage juice as a pH indicator to test common household liquids and determine their pH levels

II. Materials

Vinegar, Windex, Clorox, Coke, Black coffee, Baking soda, Soapy water, Tap water, Deionized water

Each group needs:

(1) Red cabbage juice, 30 mL

(2) Test tubes

III. Safety Information and Requirements

(1) Wear goggles or safety glasses;

(2) Dump waste according to instruction;

IV. Procedure and Data Collection

IV.1 Information and Background

In this experiment, the solution made from red cabbage is used as a pH indicator to test common household liquids and a color change produced by the pigment called flavin in red cabbage will be observed. Through the color change, the approximate pH of common household items will be successfully identified.

IV. 2 Procedure and Data Collection

(1) Obtain 5 test tubes. Add 2.00 mL red cabbage solution to each test tube.

(2) With a dropper, add 5 drops of the household liquids being tested to each test tube.

(3) Shake the test tubes. Record the colors.

Record

Liquid	Prediction: Acidic or Basic	Color

V. Post-lab Questions

(1) The following scale lists the pH of common substances. How is your prediction compared to the actual scale?

(2) Arrange the household liquids in order of in order of increasing basicity. Describe the color of the red cabbage juice for each item.

(3) How does a difference in 1 pH unit change in terms of H⁺ concentration? Example: How does a pH of 3 differ from pH of 4? Which one is a stronger acid? Why?

(4) Acid Rain: What is acid rain and how is it a problem to oceans, rivers, lakes, ponds etc?