OBJECTIVE LIFE SCIENCE
BIOCHEMISTRY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Red-colored complexes with silver
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Red-colored complexes with copper
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Red-colored complexes with mercury
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yellow-colored complexes with copper
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Detailed explanation-1: -p-nitrophenol changes from colorless to yellow around pH = 6, while the phenolphthalein changes from colorless to pink around pH = 9. Mixing these two substances creates an indicator that changes from colorless to yellow at pH = 6, and then from yellow to red at pH = 9 (Table 1).
Detailed explanation-2: -Hydrolysis of the bond frees the nitrophenol, which is detected by its yellow colour.
Detailed explanation-3: -Nitrophenols are not released from natural sources, but instead are manufactured and used in production of dyes, rubber, photographic chemicals, medicines, pesticides, and fungicides (chemicals used to kill fungus, like mold).
Detailed explanation-4: -In an alkaline medium, p-nitrophenol shows red shift since the negatively charged oxygen molecules delocalise effectively compared to the unshared electron pair.