Haloalkanes And Haloarenes

To obtain R-I from R-Cl

To obtain Ar-X by replacing diazo group of $\text{AR-N}_2^+\text{-X}^-$ using $\text{CuCl}$ / $\text{HCl}$

To obtain R-F from R-Cl using AgF

To obtain $\text{R-CH}_2\text{-R}$ from R-CO-R using Zn-Hg / HCl