MACROSCALE+MICRO.ORG...-OWLV2 ACCESS
7th Edition
ISBN: 9781305884175
Author: Williamson
Publisher: CENGAGE L
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Chapter 4, Problem 1Q
Interpretation Introduction
Interpretation:
The gray color of the naphthalene obtained after the usual purification procedure should be explained.
Concept introduction:
Recrystallization is a technique that is used to purify the impure compounds. It is based on the principle that the solubility of substances increases with the increase in temperature.
Following are some of the types of recrystallization:
- Single-solvent recrystallization
- Multi-solvent recrystallization
- Hot filtration-recrystallization
Expert Solution & Answer
Answer to Problem 1Q
The gray color of naphthalene is due to the impurity of charcoal.
Explanation of Solution
The change in color of naphthalene indicates the presence of an impurity in it. But this impurity neither lowers the melting point of the sample nor widens the melting point range. So this is not a normal small-sized impurity and it shows only color change in the sample. The color of the sample changes from white to gray so the impurity may be charcoal (black) that is used in the recrystallization process.
Conclusion
Due to the impurity of charcoal, naphthalene found to have grayish color.
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Chapter 4 Solutions
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