Question

How will you convert (Write chemical equation only):
(i) Propene into propan-2-ol (ii) Benzyl chloride into benzyl alcohol (iii) Phenol into 2,4,6-tribromophenol (iv) Phenol into picric acid (v) Salicylic acid into phenol

Hint:

Use electrophilic additions/substitutions guided by directing effects: alkene hydration (Markovnikov) gives 2° alcohol; benzyl halide hydrolyses with aqueous base; phenol is strongly activating so Br$_2$(aq) gives 2,4,6-tribromo; mixed-acid nitration gives picric acid; salicylic acid decarboxylates on heating to phenol.

Answer 1

(i) Propene \(\rightarrow\) propan-2-ol
\[ \mathrm{CH_3CH{=}CH_2 + H_2O \xrightarrow[\text{Markovnikov}]{\text{dil.\ H_2SO_4}} CH_3\!-\!CH(OH)\!-\!CH_3} \] (ii) Benzyl chloride \(\rightarrow\) benzyl alcohol
\[ \mathrm{C_6H_5CH_2Cl + KOH_{(aq)} \rightarrow C_6H_5CH_2OH + KCl} \] (iii) Phenol \(\rightarrow\) 2,4,6-tribromophenol
\[ \mathrm{C_6H_5OH + 3\,Br_2\ (aq) \rightarrow 2,4,6\!-\!C_6H_2Br_3OH + 3\,HBr} \] (iv) Phenol \(\rightarrow\) picric acid (2,4,6-trinitrophenol)
\[ \mathrm{C_6H_5OH + 3\,HNO_3 \xrightarrow[\;]{\text{conc.\ HNO}_3/\text{H}_2\text{SO}_4} \; 2,4,6\!-\!(\mathrm{NO_2})_3C_6H_2OH + 3\,H_2O} \] (v) Salicylic acid \(\rightarrow\) phenol
\[ \mathrm{o\!-\!HO\!-\!C_6H_4\!-\!COOH \xrightarrow{\Delta} C_6H_5OH + CO_2} \]