How can you prepare `Cl_2` from HCl and HCI from `Cl_2`? Write reactions only.

Answer

`HCl` can be oxidized to `Cl_(2)` by a number of oxidizing agents such as `MnO_(2), KMnO_(4), K_(2)Cr_(2)O_(7)`, etc.
`MnO_(2) + 4 HCl to MnCl_(2) + Cl_(2) + 2 H_(2)O`
`Cl_(2)` can reduced to `HCI` by its reaction with `H_(2)` in presence of diffused sunlight.
`H_(2) + CI_(2) overset("Diffused sunlight")to 2 HCl`