Question

(B) (a) Write chemical equations of the following reactions: (i) Phenol is treated with conc. \( HNO_3 \).
(ii) Propene is treated with \( B_2H_6 \) followed by oxidation by \( H_2O_2 / OH^- \).
(iii) Sodium t-butoxide is treated with \( CH_3Cl \).

Hint:

The hydroboration-oxidation of alkenes adds water in a syn fashion, which is different from the anti-addition in acid-catalyzed hydration.

Answer 1

1. Phenol treated with conc. \( HNO_3 \): Phenol reacts with concentrated nitric acid (\( HNO_3 \)) to form a mixture of nitrophenols. The reaction is as follows: \[ C_6H_5OH + HNO_3 \to 2,4,6 - \text{Nitrophenol} + H_2O \] 2. Propene treated with \( B_2H_6 \) followed by oxidation by \( H_2O_2 / OH^- \): The hydroboration-oxidation reaction of propene results in the formation of an alcohol: \[ C_3H_6 + B_2H_6 \to C_3H_7B \quad \text{(Hydroboration)} \] Followed by oxidation: \[ C_3H_7B + H_2O_2 / OH^- \to C_3H_7OH \quad \text{(Propan-2-ol)} \] 3. Sodium t-butoxide treated with \( CH_3Cl \): Sodium t-butoxide undergoes nucleophilic substitution with methyl chloride to form t-butyl methyl ether: \[ (CH_3)_3CO^- + CH_3Cl \to (CH_3)_3COCH_3 \] \bigskip