Practice Quiz

SAT Biology Subject Test Practice Questions - Question List

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51. Red cabbage (Brassica oleracea capitata rubra) can be used as a natural pH indicator, its pigments change color in response to varying pH levels.

Pigments can be extracted from the leaves of red cabbage, and relative pH can be determined by adding drops of a liquid into the pigment, as noted in the following table:

pH 1-2 Pink/Acid
pH 3-4 Dark Red/Acid
pH 5-6 Violet/Acid
pH 7-8 Blue/Neutral-Base
pH 9-10 Blue-Green/Base
pH 11-12 Green-Yellow/Base

What can a student determine about the red cabbage solution as a natural indicator of pH?
  1. It turns pink in the presence of bases
  2. It turns green in the presence of acids
  3. It turns pink in the presence of acids
  4. It is a poor indicator of acids and bases
  5. It is yellow at a neutral pH
See answer
52. What color would the pigment be after tap water is added to it?

Here is the table again for reference:

pH 1-2 Pink/Acid
pH 3-4 Dark Red/Acid
pH 5-6 Violet/Acid
pH 7-8 Blue/Neutral-Base
pH 9-10 Blue-Green/Base
pH 11-12 Green-Yellow/Base
  1. Pink
  2. Dark red
  3. Violet
  4. Blue
  5. Greenish-yellow
See answer
53. What would a student observe if vinegar was slowly added to a red cabbage pigment solution already containing sodium hydroxide (NaOH)?

Here is the pigment table for red cabbage once again:

pH 1-2 Pink/Acid
pH 3-4 Dark Red/Acid
pH 5-6 Violet/Acid
pH 7-8 Blue/Neutral-Base
pH 9-10 Blue-Green/Base
pH 11-12 Green-Yellow/Base
  1. The solution would turn from blue to green then to blue
  2. The solution would turn from pink to green then to blue
  3. The solution would turn from pink to violet, then to blue green
  4. The solution would turn from pink to yellowish-green, then to blue
  5. The solution would turn from blue-green to blue, then to pink
See answer
54. Plants get most of their colors from pigments such as chlorophyll. What is the purpose of pigments like red cabbage in nature?
  1. Indicate the pH of the soil
  2. Contribute to photosynthesis
  3. Attract animals
  4. Increase heat absorption
  5. Prevent water loss
See answer
55. An unknown substance is added to the red cabbage pigment and the color changes from blue to pink. Which of the following substances could NOT be the unknown substance?

Here is the pigment table for red cabbage once again:

pH 1-2 Pink/Acid
pH 3-4 Dark Red/Acid
pH 5-6 Violet/Acid
pH 7-8 Blue/Neutral-Base
pH 9-10 Blue-Green/Base
pH 11-12 Green-Yellow/Base
  1. Baking soda
  2. Acetic acid
  3. Hydrochloric acid
  4. Hydrofluoric acid
  5. Aluminum chloride
See answer

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