8.#phenolphthalein
1. What is the chemical formula of phenolphthalein?
a) C6H5OH
b) C20H14O4
c) C8H4O3
d) C20H14O4

2. Phenolphthalein is commonly used as:
a) Antiseptic
b) Indicator
c) Disinfectant
d) Flavoring agent

3. In which color range does phenolphthalein turn when added to a basic solution?
a) Red
b) Yellow
c) Pink
d) Colorless

4. Phenolphthalein is often employed in titrations involving:
a) Acidbase reactions
b) Redox reactions
c) Precipitation reactions
d) Combustion reactions

5. At what pH range does phenolphthalein undergo a color change in an acidbase titration?
a) pH 13
b) pH 8 10
c) pH 46
d) pH 1012

6. Which of the following solutions would cause phenolphthalein to turn pink?
a) Vinegar (acetic acid)
b) Lemon juice (citric acid)
c) Ammonia solution
d) Distilled water

7. Phenolphthalein is commonly used in the preparation of:
a) Perfumes
b) Photographic chemicals
c) Acid rain detectors
d) Acidbase indicators

8. The color change observed with phenolphthalein is due to changes in its:
a) Refractive index
b) Absorption spectrum
c) Fluorescence
d) pHdependent molecular structure

9. In which industry is phenolphthalein NOT commonly used?
a) Pharmaceutical
b) Food and beverage
c) Textile
d) Aerospace

Answers:

1. d) C20H14O4
2. b) Indicator
3. c) Pink
4. a) Acidbase reactions
5. c) pH 8 to 10
6. c) Ammonia solution
7. d) Acidbase indicators
8. d) pHdependent molecular structure
9. d) Aerospace





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