Identify compound (Z) in the following reaction sequence. [figure]
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Answer
(2) [figure]
Solution
[figure]
Dow's process: X = sodium phenoxide; HCl gives phenol (Y)
∵ –OH strongly activates the o- and p-positions ⇒ conc. HNO3 puts -NO2 at C-2, C-4 and C-6
⇒ Z = 2,4,6-trinitrophenol (picric acid)
(A), (C): o-/p-nitrophenol form with dilute HNO3 ⇒ (A), (C) are wrong
(D): only two -NO2 groups ⇒ (D) is wrong
Answer: (2)