Give the reactions of phenol with zinc dust and oxidation.

(N/A) Reaction with zinc dust: Phenol is converted to benzene on heating with zinc dust. The reaction is: $C_6H_5OH + Zn \rightarrow C_6H_6 + ZnO$.
$(b)$ Oxidation: Oxidation of phenol with chromic acid $(Na_2Cr_2O_7 + \text{conc. } H_2SO_4)$ produces a conjugated diketone known as $1,4$-benzoquinone. The reaction is: $C_6H_5OH \xrightarrow{Na_2Cr_2O_7/H_2SO_4} C_6H_4O_2$ (benzoquinone).